Thanks to a pointer by Dave Seidel, I now have an RSS2 feed. I simply added a new template to MT and pasted Mark Pilgrim's RSS2 template for MT into it. Works perfectly!
Although I'm probably the only one using it right now ... seems like a sort of masturbation to subscribe to your own newsfeed, but what the heck - perhaps I'll someday be surprised by the new items I post myself ;-)