A new screenshot poped up from the beta5 firmware version.
It appears to have a Enable 3G slider.
Official word is:
Note that this is not fake, it is in the beta 5 .ipsw, but will normally not show up on an EDGE iPhone. Turning 3G on will just crash the phone if you use an EDGE phone. If you do not believe me, then decrypt the beta5 rootfs dmg, and see for yourself in /Applications/Preferences.app/Network.plist