<< I think the R250 is supposed to the 8500 clocked at 300/300 and with 128MB of memory. >>
I hope not, because that would make the R250 no different then the already widely available ATi FireGL 8800, which is based on the R200 core clocked at 300/300 with 128MB of RAM.... of course software wise the driver set for the FireGL is quite different and optimized for vastly different uses, but functionally the hardware would be identical.