Nox 606 - that thing has GOT my attention…
I am seriously considering changing down from the DDM4K to the NOX 606.
Why?
Those 2xAux sends on each channel have got me excited.
The Nox 606 has midi-clock output. So (potentially) you could sync ableton to the audio from the Nox, and use Ableton as an external effects unit/sampler/beat sync’d sample player.
Basically - I’ll never be happy until I find a way to keep ableton sync’d to audio from a DVS system. 
wow that does look like a nice poor man’s Xone 92. I realize it doesn’t compare probably in quality or sound to the Xone 92, but at least with that if it gets stolen or drinks spilled on it, etc, you’re only out $400, not $1600. lol
Does the midi out go from the playing song or do you have to tap it on the mixer?
No matter if the midi-clock is generated automatically or if you have to tap the tempo in - it will never be that accurate that you can use to sync ableton to your DJ set, especially not for a longer time. Identifying the tempo right is one of the most difficult tasks for machines. Not even Traktor or the high-end Pioneer players get it right all the time (actually, the new rmx1000 seems to be pretty good at this, as far as I’ve heard.)
What I’m not getting here: if you are using a DVS, why not sync Ableton directly to the midi clock of your DVS??? 
If you were using CDJs or turntables, ok, but a DVS?
Regarding the NOX: as far as I’ve heard it’s just like all the other Behringer s… erm products except for the DDM4000: garbage. Cheaply assembled cheap materials. You won’t be happy for long and, I repeat myself, I’d expect the midi-clock to be one of the least accurate and stable on the market…
I’ve been looking at it too, looks like a pretty good mixer for the price. I’m prob gonna pick one up to upgrade from my Denon DN-X300
I’m using DVS on a separate laptop to my Ableton machine. Combine a tapped tempo with Mad Zach’s midi delay trick, and you’ve got some pretty good sync’ing tools…