Or you simply don’t use the "new build system”, which is not production-ready yet anyway (it’s still 0.8).
The old builds work as well as building with Maven does.
As for the initial idea. Yes, that would be cool.
Go ahead and if you have concrete problems come back :-)
I have been thinking about building an Android IDE based on Eclipse and Xtend, but didn’t get to it yet.
I wouldn’t do much more than coming up with a polished getting started tutorial and trying to remove the rough edges especially for beginners.
Also there is Xtendroid which has some nice ideas in it, but needs more love.