I got my unlocked Dell streak about a week ago. It came with 1.6 installed. When I tried to upgrade it kept telling me no upgrade available. I am currently with AT&T but wanted the unlocked phone for the early 2.2 as well as any benefits for having a non-locked phone. The dell customer service rep told me it would be released on the 14th of December but as the website did advertise it coming preloaded with 2.2 they recognized there may be a problem. I ended up taking the sim out of the phone and tried to update over the wifi and it found the update and I am currently running an official 2.2 on the unlocked dell streak. Once installed, I just popped in my AT&T sim card and it worked flawlessly.
Alpine White Mini 9, 2Gb ram, 64Gb Runcore SSD, 1.3MP cam, internal BT module, Dualboot Win7/OSX 10.5.8
Unlocked Streak, Streakdroid v.1.9.0
XPS M1330, 4Gb ram, 320Gb HDD, 128Mb Geforce 8400M GS, Wireless N, internal BT module, Slim and Brite LCD, Windows 7 Ultimate