Mark Bernstein is playing with adding support for Macros to Tinderbox. That's such a good idea that I wish I had suggested it. Tinderbox clearly has a powerful text substitution and resolution engine under its hood, and exposing it in a way that lets users create their own macros, resolved at export time, is a neat idea. The complexity will surely befuddle some users, but I'm hoping it makes it out of the lab and into the product soon.