That's interesting.
As I get it, the business model would rely on some kind of licensing obviously, so even if they release the full RTL source code as open source, which I'm not completely sure of yet, you are probably just going to be able to play with it and not much more.
As for FPGAs, given the general specs of this processor, you would probably need a pretty big FPGA just to be able to put a single core of it...