http://www.natami.net/knowledge.php might be a forum for this. There's talk there of making a consumer-grade Amiga-compatible chip out of a FPGA chip and some other logic using 16-bit memory busses. Of course the developer version will be more expensive but also more powerful with 32-bit memory busses. The Natami aims to put all of the chipset functionality on one chip including an experimental new 68050 processor core.
Also, I'm planning on working on a GLSL shader implementation that will imitate the functionality of an Amiga graphics chipset without outright emulating all of the timing of each function. It's intended to be just enough gusto to make Amos Basic code work on non-Amiga graphics chipsets.
