> I bet Imagination Technologies would request you a lot of money
> for the PowerVR documentation.

Concluding from past postings on powerdeveloper.org, THTF/Cherrypal or whoever could even obtain driver source from Imagination Technologies and distribute a binary if they wanted:

http://www.powerdeveloper.org/forums/viewtopic.php?p=9045#9045
http://www.powerdeveloper.org/forums/viewtopic.php?p=9534#9534
http://www.powerdeveloper.org/forums/viewtopic.php?p=10238#10238

I don't know the costs of such license though.