To be honest, I've been thinking about using a Dynarec for SpecBAS. There's only so far a stack-based bytecode implementation will take you for speed concerns. But then, SpecBAS doesn't really need it as nobody is using it for CPU-intensive tasks (and that's not a job for a BASIC in any case, IMO), and as all the heavy lifting is done via my library of support routines, the language itself is just a method for calling that at the end of the day.
To be fair, I suppose if LuaJIT is BASIC-alike enough in its language implementation (and that's a very, very wide field these days - we have strayed so, so far from Dartmouth) then it can indeed be compared to others.