I do not know of any switcher that has DMX control, but most have RS232 control. You could use something like this from Doug Fleenor to turn DMX control into RS232 command into the switcher.
http://www.dfd.com/232.html
I have never done this, but it could work in theory. Check this out and do your research. Give Doug Fleenor a call and see if this product will do what you are looking for.
Good luck and report back,
Sean
At $1432, there's got to be another way...
If you've got a free dimmed output, and can change it to on/off in your dimmer, I'd consider getting a relay-controlled switcher instead, and a Furman PS-REL. Tie the NO to input 1, and the NC to input two.
Of course, this relies on your dimmer being able to fully shut off the power to the output. But for under $50, it's worth a try.