Personally, I think the best thing he could do would be to opensource the project and finally allow it to be ported to Linux. If he's worried about revenue or whatever, add a donate button. I'd pay _more_ for a FLOSS version than I would for a proprietary one.

Right now, I love TextMate. It's the best text editor out of the box, but the fact of the matter is: OSX is not my only development machine and the hassle of learning Vim keybinds is less painful than only using OSX for development.