So, you can now buy the xpPhone...
Goes between $666 for one with no cellular modem, 8 gigs of SSD, and DOS, to $876 for one with an 800 MHz CDMA/EVDO modem, 16 gigs of SSD, and "Windows Embedded Standard 2009" (read: XP with a different name, might be NT 5.2, but...)
Looks like it's got either a Geode LX 800 or 900 (nobody's sure which,) which is, to be honest, a fairly slow CPU. The "800" and "900" numbers are PR numbers, but rather than being relative to the Pentium 4, they're relative to the VIA C3. Yeaaaaaah. That said, in a video hands-on
Interestingly, the modem is Mini-PCIe... so, you find a voice-capable modem that does what you want, you pop it in, install the drivers... and voila, it works on that band and mode.
Size... it's huge, but... if you think of it as a wider, slightly thinner DS Lite (which is what it is, dimensionally,) it's still on the edge of pocketable.
Battery life sounds like it might not be dreadful - 4 hours talk time, 7 hours non-radio usage time is apparently realistic, and they're claiming 5 days standby (because it's just powering the radio and the RAM in standby, and the radio itself would be idling until a call comes in, which sends a wake-on-modem to the PC.)
Now to decide whether I want to spend $900 on a phone... (It's about $100 shipping, on top of the $800 for the 8 gig with modem phone. I'll get the non-modem model if the included modem doesn't support CDMA 1900, though, and find my own modem.)