Brian McCallister has done a plugin for SubEthaEdit which is here.
A new-format language "mode" for SubEthaEdit 2.x is available here.
VIM has been done by Alessio Pace here.
A language specification for Apple's Xcode IDE is available here.
Guillaume Laforge wrote a syntax file for the TextPad text editor which can be downloaded here. This file should be installed in the Samples subdirectory of your TextPad installation.
Jeremy Rayner has written a groovy-mode for emacs, details of which can be found on the Emacs Plugin page.