No integrated headsets!
Good lord I hate those things. The bearings aren't made to any kind of actual standard, you have to use a significantly heavier and more expensive head tube (so the weight is a wash - you don't save a thing) and if something goes wrong, replacement parts are hard to find.
To be honest, in the size of frame we're talking about, stiffness isn't much of an issue, so if bar height is a big problem, either find someone who will build around a non suspension-corrected fork, take a riser stem and flip it over, trade in your riser bars for flat, or all of the above. And if those things don't get it low enough, you shouldn't be on a 29er.
Hey Cloxxi - how's this fork appeal to your sense of aesthetics? No silly spacer, eh? It's a bit of a proto, I've been riding it around for a couple weeks now - this one is made from straight-gauge .049 cromoly, which means it's a total pig and stiff as heck, but the next one will actually be made out of decent stuff (figure 2 pounds instead of 3).
-Walt