I have been so focused on Web 2.0 stuff that I've been reading a bunch of new blogs and disregarding the old ones I used to read. So I didn't realize until today that the DSL Tools team released a new drop last week. According to Gareth, the highlights include:
Update: Apparently, I can't read. Only the VS SDK integration is done in this build. improvements to the file format and model serialization will be in the next drop.