I remember reading about the troubles the 37signals guys were having with supporting textile in their products from this year-old thread: http://forum.37signals.com/highrise/forums/9/topics/802.

At the time I wondered if they might be considering developing a wysiwyg editor that integrated with their products better than what is out there.

I found the thread this summer while I burnt a fair amount of time looking at various lightweight markup languages and all the wysiwyg editors. I eventually just decided to put it to one side for now and maybe just code a few simple formatting helpers myself. I am very interested in seeing where this goes!