Yeah, you have to know or ask, but Hank sells nearly anything if you ask.
For example someone else git a D4S Aux emitter board with red LEDs from Hank.
The same with Simon from Convoy on AliExpress. You can get any combination of host and driver from him.
This thread was helpful to me. I also removed the R5 resistor while pushing out the D4 driver.
Then it got worse, I removed the wire from the switch side.
Anyone got info on getting the switch out?
It’s super easy to rip that thing off haha. Glad it helped you! Thanks for the reminder that this thread is here, I meant to update it with my latest experience.
TL;DR: I’ve confirmed you can successfully bridge the R4 resistor and the light should be fine.
While disassembling my buddies D4, I managed to pop off the R5 AND R4 resistors, oy… we got them both back on and the light was acting extremely odd, no strobe modes would work at all, and if you entered turbo, you could not exit it without disconnecting the battery. Also occasionally it would fail to ramp out of regulated mode, just stopping at the end of regulated mode and staying at that brightness. Very weird.
Turns out the connection we made when resoldering R4 was no good. A little more fiddling with the iron and it was right as rain. Mostly…
I then ran into the problem wherein the light would act up in the same manner as it was when be R4 was disconnected, but only when it was super hot. I figure the connection on R4 would only fail if the board got hot enough to expand a small fissure in the solder joint.
By this time I had gotten my hands on some good solder wick and a tub of solder paste so I planned to fix it properly, but when I got it apart and got the resistor off, I dropped it into a large thick shaggy rug… never to be seen again…
So I just bridged it and prayed. Lo and behold it works just fine, ran it through all modes. So it’s seems I’ve confirmed you can bridge R4 as well with no issues.
I need to be more careful with these stupid things haha.
Edit: I didn’t see your remark about ripping out the switch wire, that sucks man. I’ve seen advice somewhere on how to get the switch out, I can’t remember where, look for D4 switch mods, that’ll get you on the right track.
I would guess before long TK will chime in here, she’s the good fairy of D4’s and several other lights as well. 
Re attaching the wire is possible, but I have heard it’s a pain. I just bought and installed a new driver in my D4 and it came with the two white switch wires attached to the driver.
I have 19 R5’s, I broke one of those also. As noted above, you can likely get away with just shorting it out. PM me if you want me to mail one to you though (USA only).
@beastlykings, If I recall correctly R4 is in series with the FET gate. Likely not a problem to short that out either, but it is good practice to put a resistor there to dampen any possibility of oscillation.
Have a replacement on order. Was getting frustrated so I took a break and bought some stuff. lol
will look for post on D4 switch removal.
Thanks
Just wanted to update this post with some new information I wasn't aware of. It seems Hank has increased the size of the hole in the driver head, this made the driver removal MUCH easier, and I didn't damage anything this time around.
New head:
Old head:
I know this is an older thread but I’ve replaced the emitter in my Drs with a green NM.1 Osram. Worked out well except I can’t turn the dang thing off. All the functions work fine. Ramps up and down. Double click to turbo and click down to regular. Just won’t turn off. I have to turn off and on by the tailcap. I’ve checked for shorts on the leads and everything seems fine. No clue why it is doing this and am unsure if I want to replace the driver with the switch leads being so short. Does anyone have any ideas what else it could be. Seems the drivers have no ground rings like the lights I’m used to seeing on drivers. Is the mtn 22mm driver really work in these? Did you guys have to glue them back in or do they stay in on their own?
Usually a light won’t turn off because a wire is trapped and shorting to the body. (I’m unclear why the rest of it works in this case, though.) I did re-glue my D1 and D4 driver boards after flashing with Anduril to prevent the driver from rotating when the body tube is screwed in - and possibly stressing the wires.
Thanks for the input, Brewster. 