Thinking the Ultrafire UF-2100 is pretty compact but never having seen one in person don’t know exact size. Is that about as small as they come or are there smaller ones?
I think the Shiningbeam S-mini, but the YEE-Lic or this one are in the running: https://budgetlightforum.com/t/-/8578
This thread might help you.
This one looks like it might be a contender http://www.ebay.com/itm/CREE-R2-500-Lumens-LED-Stainless-Steel-Flashlight-/180861990372?pt=LH_DefaultDomain_0&hash=item2a1c36f5e4
Can't say I know anything about it as I've just hoisted it straight from Burro's new thread https://budgetlightforum.com/t/-/8570 
Does look interesting, though..
I've vote for the S-mini
S-Mini all the way (22 mm diameter... only 0.5 mm more than the Xeno E03 which is 1AA!)... I own the 2100 too... landslides difference in price, but also in quality. Will do a small round up on compact (XM-L) lights next weekend. (S-mini II, 2100 and TR801)
Hi Vectrex, I'd love to see that round-up.
Also in brightness too right? Isnt the s-mini only 1.0A on high? I love the s-mini's looks and knurling but according to my figures, my 2100 on med should be brighter than the s-mini on high.
Can you verify if this is true? Also, how much smaller does it feel than the 2100?
Thx
+1
I've a TR-801 on the way: http://www.ebay.co.uk/itm/150430431517?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
partly because I just couldn't decide which 2100 version to get. Was also going to order one of these Manafont.com | $14.02 Ultrafire A10B Q5 5-Mode Memory LED Flashlight (18650) but I'll hold off until after I've allowed Vectrex to influence my decision
Relying on you, Veckers! 
Yep, the S-Mini is certainly not the brightest compact XM-L light, but I like the brightness vs. runtime ratio a lot... I think most people run their 2+ amps XM-Ls most of the time in medium if they look at their usage profile. The 1000 mA also has the benefit that you can use any emitter that you want in it.... from high CRI Nichias to warm/neutral XM-L. Since the flashlight body is so lightweight it's probably better that it is only 1000 mA on high, because it has not much thermal mass.
Kreisler the Xeno S3A is nice looking, but only 300 Lumen for CW and 280 Lumen for NW... problably driven even lower than the S-Mini due to even less mass. (21.5mm (diameter), 111mm (length))
oo i dont like too much about the new xeno tbh. so what's special about it? yep, that it's very thin, 21.5mm is thinner than the Quark and P2A. specs, looks, haptics, .. not very impressive from the standpoint of a critical potential buyer.
but it's good to see some new product from them.
people will be very interested in this new flashlight no doubt .. and why? only because Xeno has a single success story with the 'legendary' E03. I find this phenomenon very instructive. New flashlight manufacturers need to learn a lesson from the E03 example. Any of them needs a best-selling product in order to firmly break into the market and gain a foothold.
Thanks for the link Vectrex. It's in Chin*se ;)
haha
btw, you never shared in detail your thoughts and observations regarding your S-mini sample..
Yep that's why I intend to do a small round up in that class (see post #5). It's a pity I don't own the Eagletac D25LC2, which was also on my radar before I bought the S-Mini II... would be nice to include in the round up.