Met de Iphone schijnt het te kunnen:

Spoof IMEI on firmware 2.2....
I did not originate this, I just slimmed down the amount of steps from here(homeofmagic.blogspot.com)

Step 1: Install itunes 7.6 or 7.5, reboot and downgrade to 1.1.4
(The firmware can be found on here)
Step 2: you can use ziphone or iliberty to activate, unlock, downgrade basehand to 3.9fakeblank
Step 3: Use ziphone to change you imei to your desired # (i.e a gophone imei or whatever)
Step 4: Install the latest itunes, reboot, and install the firmware here: homeofmagic.blogspot.com
Step 5: You now have a 2g iphone with a spoofed imei and you know what that means.......Working swirlymms!!

**YOU CAN USE THE SAME CPU TO GET THIS WORKING UNLIKE THE ORIGINAL INSTRUCTIONS
**YOU ARE ALSO NOT LIMITED TO ZIPHONE WHEN IT COMES TO UNLOCKING/JAILBREAKING