I have decided that rather than brew up a custom theme (Indric Builder), I am going to import directly the Artificer from the Eberron setting. It is almost exactly what I was going to invent anyway, and all the work is done — and hopefully reasonably well-balanced. In order to make this work the way I want, I am going to create an Artificer theme in the same way that 4e At-Will has been doing classes-as-themes for multiclassing.
The other thing I’m bringing in — athough I am going to meddle with it a little bit — is the Warforged race. The Indric-era elves were big on constructs, golems, and automatons, and it’s very in-character for some of their designers to go so far as to make the things conscious. My biggest blocker is to find out a source for minis that isn’t going to cost a fortune.
I don’t think I’ll invite any of the other races, except I might take a sort of Eberron-like slant on dwarves. I might allow them as a minor race that aren’t “dwarvish” in the usual way, but rather are more like a wealth-obsessed human offshoot. Like what I imagine Sumerian nobility to be like, with oiled and decorated beards, only a bit shorter and stockier. None of that Scottish accent stuff.