I've been thinking for a while about starting to work on a Cocoa
version of XEmacs for MacOS X.
Both GNU Emacs and XEmacs have a Carbon version running on MacOS X.
However these versions do not take advantage of the very nice features
the Cocoa toolkit provides. The NSText system allows writing an editor
really fast. The next step would be to make the Objective-C components
of the editor available to the Lisp engine, and possibly to other
interpreted languages as well (Python would be very nice).
I've started building a small prototype for this idea.
Ovidiu