Yeah, have you check out Parrot? It also let's you use Python + many other languages in the same VM. I'm interested as to how that would apply or NOT to a system like construct. Parrot and LLVM, etc are supposedly faster running than Python. It's interesting but not sure how that would be applyed to construct.I didn't see anything about not being able to use libraries of Python just because it's in Parrot, but I'm no expert just out of pure curiosity this is interesting. If it was added to construct it would mean no need to force people to use just one language and could have multiple developers that are experienced at separate languages on the same project.
-edit- I'm guessing with these the problem is they are just not ready yet for some reason or another. It's cool that you can easily use it to compile your own created programming language tho. And that program will be automatically cross platform. If these types of VM are not widely used yet, It'd have to be because of something like a problem with completeness or speed compared to just plain c++.
Interesting concept for the future tho.