Scott-

I'm up in Oakland, but if you don't get any local nibbles I might be able to help. I've built a few of these devices and although I don't have one "off the rack" to offer you I'm fairly well tooled-up to build one to spec on short notice. It would cost you around $300, built mostly from new parts, including new hoses and fittings, and an electric trigger mechanism. It would require a 120v AC power source for the trigger so you'd need a regular power outlet... an inverter and 12v battery or a generator if your application is portable.

Here are some video clips of such a device I assembled for a friend's art car:
video.yahoo.com/mypage/video

Would something like this be suitable?

You should know that if this is for a Burning Man mutant vehicle there are additional regulations and permit inspections required. For example, the flame outlet must be at least 10 feet above ground (so you don't accidentally blast cyclists and pedestrians) and there must be a quarter-turn quick shut-off safety valve within reach of the driver.

Also, you should be aware that after an hour or so of intermittent use (with a steady pilot flame), your propane fuel tank will start to freeze up and you'll either need to switch tanks (if mobile), or keep your fuel tank submerged in a large plastic tub filled with water (if stationary) to maintain a high enough fuel temperature that the pressure will still be high enough to be impressive from 25' away. Switching between a couple of different fuel tanks periodically is probably the easiest way to go.

Let me know more about what you're building, what your budget is, and your time frame, and perhaps I can help you out.

cheers,
shawn shiva.