We (I myself to development it in fact) will run it for SPARC, SuperSPARC and UltraSPARC. To be honest, I don't hope to learn Forth, as I am C/C++ developer.
Do you have any suggestions?
Not that I had any suggestions, but I think if you plan to use any of a standard desktop/server OS for SPARC on your hardware it would be easier with Forth because the existing bootloaders expect it.
Or are you going to use it with some non-general purpose embedded OS?