The guys at UltraEdit finally added a link to Perl Oasis like they said the would. Nice!
I'd better release a new version soon. I have implemented support for PFE (semi stable) and gVim.
Asking about supported features in an XEmacs list resulted in... well, undef. Oh, well.
TextPad seems like a popular editor, although I'm not 100% sure it has the required capabilities to integrate Oasis with it.