RaptorJIT has a mostly finished port of the bytecode interpreter to C. That should make new arches /much/ easier to support because you don't have to hand-code a VM in asm, only write a JIT assembler backend. Check it out at https://github.com/raptorjit/raptorjit/pull/254

Current status is that it passed the LuaJIT test suite but that's not 100% coverage and it doesn't call into the JIT yet.