My homemade custom 29er runs chainstays at a smidge under 16". Combining this with Sam's Hummingbird fork (55mm offset) and a 70 head gives rather nice handling in my opinion (I'm 5ft 10" so my weight isn't too far back). It won't suit everyone but I'd suggest people under 6ft shouldn't flame the idea until they actually try riding one. It is just another way to get a sensible wheelbase 29er instead of the normal long stay / steep head angle route.
I can't / don't run a front mech. Usual setup is singlespeed but took it to the alps this summer with 5 cogs at the back and it climbed just fine (not lifting the front wheel). 2.4" tyres and bags of mud room thanks to subtly elevated chainstays (just enough elevation to clear chain running 32:32 max ratio).
I put a big curve in the seat tube to clear the tyre but most others are using a straight tube joining the downtube ahead of the bb shell.
Starting to get a reasonable range of production models (Canfield, Kona etc mentioned above). However looking at some build photos I'm a little sceptical of some of the claimed chainstay lengths - there seems to be a lot of daylight between bb shell and tyre on some photos of bikes claiming 16.25" stays
Will be building another next year to suit a suspension fork and maybe with regular stays (there is room to fit them with careful design and a single chainring).