So, I bought these boots because they were the smallest non-plastic moutaineering boots that I could find. That, and let's face it, they're bright green. Having tiny feet and poor circulation, I was naturally worried about two things: sizing, and warmth. Having taken them out on a few occasions now, I feel as though I can comment on them.
Sizing: I have a pair of old Scarpa leather hiking boots, a half size smaller than these - the fit is as I hoped it would be, although I do have to wear an extra pair of socks. The moveable tongue insert thingie really allowed me to make room for my super high arches yet lace the boots tight enough to eliminate heel slippage. Awesome.
Warmth: these baddies are surprisingly warm for leather boots, though the fact that I can actually move around in them probably helps. They play very nicely with my crampons, too, although I might have to bend the front piece a bit to accommodate the narrow toe box. I took them out in 0-30F weather, I'm interested to see how they work in sub-zero temps, though.
Overall: I am extremely pleased with my tiny mountaineering boots.
UPDATE JAN 2012 - wore them in -10F w/ 40MPH winds, still warm as long as I kept moving. Would probably want some double boots for temps much colder than that.