A lot of the work in 1.9 and 2.0 has gone to better unicode support.
Most string handling functions are now codepoint aware, and there is now
the ability for the source file to have an encoding attached to it.
Like Curt said, these are in flex, but they are spec’d in RubySpec, so
they are more than just fleeting ideas.
If you are able to solve this with an extension method, then it looks
likely that any VS integration work for IRb will take care of that. As
it is, I use GVim for most of my Ruby coding these days.