Thanks for letting us know about these tools.
We've already audited jEdit and found that it hadn't been written with reusability in mind - it's a great editor, but the authors don't appear to have designed it to be easily transformed into a component for another software. This was years ago however, so this might have changed. We'll probably need to take another look.
As for jVi, that sounds like exactly like the sort of component we're looking for - except for the fact that it's vi :)
Don't get me wrong, vi is a very good and very powerful text editor, but you can't put it in anybody's hands. Some people have been known to slam computers against walls after spending half an hour attempting to work out of to save a file.
I'm an Emacs man myself, and I would be against integrating an hypothetical jEmacs package. Our goal is to make muCommander as accessible and intuitive as possible, and using vi or Emacs or any such "old school" text editor runs against that goal.
Again, thanks for letting us know about these projects. We can't really integrate them, but it's always good to know what else is happening in the Java world - we might, for example, be able to re-use some of these projects' code or components for our own text editor.