Or if it is an HTC. So throw out another 50% of devices out there.
I'm on a HTC Hero... rooted, and running aospCMod (AOSP 2.3.4 / CM7+ (Gingerbread)). I don't have a Sixaxis to test the actual hardware, but the compatibility checker indicates that my phone is compatible.
So maybe not completely "throw out another 50% of devices out there." Mod'ed HTC's may be good to go, and a mod'ded phone is guaranteed to be rooted.