I am very tempted to go to my local Sprint retail store and carefully open up a U720 EVDO modem and try it inside my Q1U to see if it boots up and works with the U720 software. If it is properly recognized in Vista, I plan on simply using the internals of the U720 antenna assembly and finding an open space to place the antenna. I do not believe the plastic casing on the Q1U will attenuate the wireless signal enough to make too much of a difference.
I would much rather opt for an HSDPA solution so that I can use it internationally, but by the time coverage is up to par with Sprint's EVDO network in the US, I would have already upgraded my UMPC a few times.
Now, the most important question here is whether I can open up the U720 without damaging it or breaking any stickers that void the warranty making the product non-returnable just in case the BIOS in the Q1U is indeed locked. The previous poster has made it almost very clear that it is indeed locked. I am always hoping as the BT connection to my phone is the bottleneck of my current WWAN connection.
Cheers.