May or may not be helpful, but in my band playing days I used an Obey 40 to run a few strip-LED type fixtures over DMX, taking a midi control change signal from my guitar pedalboard (tc electronics) so that as I changed patches, the lights changed scenes. I had a lot of programs in my board for various songs, so I could pick a "look" that went with that particular part of each song. It was as on-beat as my toe-tapping effects changes allowed, and we were pretty tight in our heyday so it worked well enough for small gigs (bigger gigs the fixtures just didn't keep up, and we had a lighting tech for those).
My drummer and I often talked about expanding this concept with some form of drum trigger in his kick drum for additional input. It's easy to generate a midi signal from a trigger, and the Obey 40 was pretty inexpensive. It's been many years, but I seem to recall there were midi devices that would generate a tempo command based on a "tap tempo" type of input, which is what we wanted to do since our songs changed time signatures too often/didn't play to a click so sometimes the pre-programmed tempo of the lighting scene wasn't quite on par (although some of the scenes made a good "silent" click track sometimes). This is where I think it might expand to something more useful to you, I just can't remember the names of any of the devices we were looking into and it never came to fruition (like our third album).
In our application, we owned the lights as a band and the drummer hand built his drums, so it would have been easy to integrate trigger in the kick with a midi connection on the shell. Not so much for the sound provider side, but I see no reason you couldn't use a similar concept using an audio source as a trigger like Andrew suggested if your board allows it, but the midi workaround for me worked very well and midi gadgets are relatively compact and inexpensive (i'd wager cheaper than any software/computer setup if you're not already bringing that out). Perhaps there's something out there that can take an audio input and generate a midi tempo? Then it would just be a feed from the board or a Y cable on the kick mic or something simple.
