Out of curiosity, why the dependency on MacRuby? The only thing I've seen in the digging I've done thus far is the CFUUID stuff, but that is easy enough to recreate in Ruby so I think I must be missing something...
I suspect that you'll see many more benefits of using MacRuby for the project going forward. For example, think about the sorts of things that Bundler (being written in Ruby) can do for Ruby gems that rvm (being mostly written in shell script) cannot.