Sorry, but I'm announcing another Mac-only thing to the ConTeXt list.
I'd like a few testers on an export script. OmniOutliner Pro makes for an interesting structured editor, and I've written an export plug-in that outputs ContML code that can easily be run through ConTeXt. I could use a couple savvy MacOSX ConTeXters to help verify it's behaving as expected and that it's usable.
It means running a (99% stable) beta application (OOPro) that won't be free in the long term, so if that offends your sensibilities, turn away now... (My plug-in and ConTeXt module will be free, of course.)
If you're interested in helping out, though, please send me a message off-list, and make sure you have OmniOutliner Pro beta installed: http://www.omnigroup.com/applications/omnioutliner/beta/pro/
I'll be sending out a package in a few days.