I posted this earlier in the newbie section, but as my account is now fully enabled...
Lenovo T61 laptop works great booting BT4 beta from USB. Wireless works, although I haven't tried anything fancy like packet injection yet (will update when I do).
I'm currently having issues getting BT4 to recognize a Swiss keyboard, but as an American by birth, I've luckily got the US keyboard layout memorized. And that's got nothing to do with the laptop model anyway.
Also got a T61, works well for me too.
I have also already injected with its intel 3945 card successfully!
The only problem i got is that it tells some errors when i try to check the contents of a pendrive plugged in.. :S