OK, so in the order these have been asked...
3G works on both Demo K3 units I've tried and both Demo DXG units. Mind you, I haven't done anything but registering over 3G, so you might be out of luck if you want to use the built-in browser extensively, but the hardware is indeed there.
I use this for sniping:
https://www.myibidder.com/ They also have browser add-ons, so you just see a "Snipe it" link next to Facebook/twitter icons when viewing an auction.
Now I'm kind of lost at what you've won, but short of DXGs, I'm interested in a few K4s/K5s, so let us know how many are in actual working order once you get them.