I was pretty impressed by the SAFARI presentation by Bob Fuhrer from IBM Research. They have a lot of tooling that generates most of the cool features you get with an Eclipse language IDE, for any language that you specify. There are lots of wizards that generate Java plug-in code and most of it finds information based on a grammar you provide. A lot of it is pretty simplistic, but enough to get you going. At the very least, the generated code can serve as a great head start.
The good news is that they are close to bringing it to Eclipse for others to use. Of course we’re building a multi-language framework with the CDT. So we’ll have to figure out where we can leverage some of the cool things they have and where they can leverage some of the cool things we have. But this will be a great tool to help those poor souls who ask us how to build an IDE like the CDT for their own language.