The OpenGraphics project (OGP) is a nice thought but uses high end FPGA where the cost for chips and route-and-place tools is prohibitive. So it's in practice a no go solution. It's better to polish your knowledge in graphics and start from scratch. Do less, do the important and be confident that it's enough (less is more). Are all functions of the PS3 really needed? if not which one would be the most important ones?
Everything is of course a tradeoff. If one wants, PS3 graphics, as the person I replied to suggested, then one will pay for it. If one wants something relatively inexpensive, then one might not get PS3 level graphics. Especially in an FPGA, compared to Sony's custom ASIC. The overhead that makes an FPGA able to "be anything" will slow it down compared to the custom ASIC. Plus, Sony had a big team of specialists and a huge budget, as do Nvidia, AMD etc., compared to the people willing and able to work on such things for open-hardware, or even proprietary in our kind of market, so our results may differ from theirs from those things as well.
