something like particle illusion would be perfect for this. :) Have a copy?
If not, making an animation (maybe a gif) of the burn & using trackmotion would work. Photoshop/Gimp have defaults for making a sparkish trail I belive.
there's a couple sparkles/fireworks/fire that could be modified for the effect he's looking for in PI. I just checked the fire, fireworks & sparkles lib's & there's several good ones. :)
I would check out Particle Illusion as well. I used the demo and the free downloadable emitter libraries to do a burning fuse accross the bottom of the screen a la Mission Impossible. It came out great. It was real easy to use as well.
There's always a bunch of suggestions for "something else". Well, here's one for Vegas - the text generator and the light rays plug-in. When you see this example you'll see that you could easily tweak it into looking like a burning fuse. Learn how to keyframe effects, that's all you need.
Everything in the example (other than the horse and the audio) was done with fonts in the text generator, pan/crop and light rays.
Tor
I'd probably use one of digitaljuice.com's new "revealers", which are alpha-channel rendered small fx, many include fireworks/flame that could be used for a MI-style fuse burn, if combined with a stock photo of rope/fuse..