Well, I suppose then in this case, I might end up being the one to solve the riddle. I shall give it a shot and let everyone know what I find!
For a keychain I think length / weight and material are critical as well as the 20/100 lumens you were looking for . The Dqg two mode NW clicky was a perfect keychain light for years until mine just finally bit the dust . I tried a $5 just pay shipping one mode Olight but one mode is a deal killer for me . A old version lumintop tool with the med/low/high and a 219B would work if i had the tailcap to turn it into a twisty . I don't mind the idea of a AAA keychain light but it has to be really small .tried to use a sofirn and think the two modes are pretty good but it's just a lil long ,Same as the old trunite original ti ...just a bit bigger than I want to be hauling around .
The rovy vons and nitecores etc with usb rechargable batteries may be the way to go but they aren't available at real budgety prices and all seem to have their own issues . Some still plagued with deadly PWM .
keep up the search .
size matters 
No doubt the olight i3e /SKILHUNT e3a are very attractive options for keychain carry due to size—BUT I so wish that they would make a multi mode. AAA light that can only do 100 lumens? It doesn’t make sense to me. If they gave it a 2 mode driver like the C01S it would be the perfect aaa light IMO.
I agree that the single high mode on the Olight is not practical for me.
I prefer three modes.
size matters, but modes matter more
and High CRI matters even more, to me:
I’ve eventually settled on the Thrunite Ti3 NW on my keychain. I picked up a couple and most are a creamy neutral similar to a neutral malkoff (probably because they are both XPG2). One of my samples is a bit warmer and works out very nicely for my keys. Still very bright on high but the moon mode is nice and warm and easy on the night adapted eyes. Would be easy to swap LEDs if desired, and in fact I have done that on two of the titanium version.
another option
Lumintop Worm
and
I have not tried to figure out the specs, so I dont know if the worms are available in High CRI
note that worms have no pocket clips, which means they will roll off a table…
The Ti3 has a nice reversible clip option
I prefer MLH, but afaik these are now all LMH, like the Ti3
but the Ti3 low is sublumen of 0.03, on a Worm its about 5 lumens
I find it rather aggravating to have to double twist the Ti3, as I seldom need 0.03 lumens, so I dont like it to come first in rotation
but, the LMH lovers got their wish 
I prefer a center hanger, so the worm wins over the Ti3 on that account also
and the worm now has a pebbled TiR, which makes a very useful beam, imo better than the Ti3, for the intended close range use of an AAA…
On small EDC or key chain lights, I like LMH or LH depending on the low. The 3-mode Massdrop Brass I passed your way and the 2-mode C01S have what I consider to be useful lows. I don’t mind twisting up from there when I need it because I don’t always need it. Compared to knives, I see lights in this category more like Swiss Army Knives than fast-opening full-sized folders.
I get why people like moonlight out front. It's great for preserving night vision and getting extremely long run times. My problem is two-fold. First, I'm almost never in a situation where that matters versus a normal low. Second, I'm almost always in a situation where moonlight is too low or I just want a little more light. So it means extra steps for no good reason.
Honestly, the only time starting in moonlight has real value for me is at night if I'm camping or when there is a long power outage. In those cases (and whenever I'm wearing a jacket with pockets), I've already got an 18650 flashlight with Biscotti and I can make it so.
I have a C01R in the mail, so I will try to change out the emitter and see how it does for this.
Like jon_slider I do see the MLH or MHL as great modes for certain situations.
If it was programmable in what order you wanted the three modes I would just program before I went out to the option I most needed.
By default it would probably set to MHL for me, but on LMH for outdoor trecs.
good idea, I look forward to your success
fwiw, another flashlight UI option,
Some lights have Last Mode Memory
it lets you “program” what level the light turns on at…
The Jetbeam AAA has memory,
if you use it on Medium during the day, it will keep coming on at Medium until you change modes
same if you use moonlight at bedtime, it remembers
I personally have not learned to like memory, but some people find it very useful
The C01R is programmable to LMH or HML. Perfect UI for an AAA light IMO.
I wish they would replicate it in their C01S.
think a Two Mode makes perfect sense on a Keychain Light . The perfect light on a key ring is stainless because it matches keys without standing out takes a beating without looking like hell . No PWM is obviously a must and a moon on a keyring to me is almost out of place .
I'm a pure tint snob and believe every light ought to be high cry ..BUT in the case of a light on your keys I understand that the point here is a very quickly used light that's objective is to SEE . where as a regular flashlight is one where a person wants to LOOK at something .
The idea of Looking vs. Seeing has gotten me thinking about what's expected when a light goes on . PWM is seen as just a nasty distraction but what are the goals or expected outcome when turning on a light .
I see seeing as wanting to avoid an armchair,seeing the toilet or a LEGO on the floor .
While looking is more of an inspection ,detailed and wanting more information .
The topic of discussion comes up and how people use a light needs to be looked at a little closer . Picking up M&M's that have fallen down behind the couch is obviously different than looking at a photo or cooking food.
A key chain may get a pass on high cri or not since it's used so infrequently . whether you wish to mod it or pursue a tint ,hue and cry the choice is up to you .
I have the Sofirn and the Astrolux, Astrolux is somewhat better.
> The idea of Looking vs. Seeing has gotten me thinking
interesting distinction…
Seeing the Bear before he eats you is more important that Looking at all the lovely colors in his fur… So yes, Low CRI is enough to identify a threat, but High CRI gives a more accurate picture.
> Picking up M&M’s that have fallen down behind the couch is obviously different than looking at a photo or cooking food.
true, as long as you dont care which of the M&Ms is the Orange one, cause with Low CRI its going to look brown… lol
and yes, food is disgusting in Low CRI.
Looking at a photo also benefits from a floody beam, such as a pebbled TiR, to reduce glare, and the need to wiggle the hotspot around to find the best lighting.
> tint, hue and cry
I see what you did there… LOL
I put a TiR in a Ti3. It is very useful at arms length
the beam on the right is the TiR:
Im raising a Hue and Cry that good Tint is the only way to Fly
I find the Tint of Low CRI makes me Cry
We live in a world of superlatives. Fastest, lightest, and yes brightest. A light capable of “looking” can be toned down to simply “seeing.” On the other hand, if the best you can do is see, then looking will never be an option.
The idea being a Ferrari can go the speed of a Hyundai but the Hyundai cannot go the speed of the Ferrari.