Please read for an updated status on RailsCasts:
Learn more or hide this
GitHub User: fbehrens
I have the same problem I found out that ZSH (and oh-my-zsh) works in windows under cygwin which emulates a *nix environment. It's a little bit slower, and i had some quirks buts its worth a try.
For Windows users, the amazing reloading mechanism on edit-method works fine when using GVIM and set EDITOR=vim
I once got some colorful working with ansicon and those .irbrc . Some more fiddling may be required, hope that helps, Frank