Anyone used one to shoot fireworks? I tried a tripod last year but spent most of the time guarding it from being kicked over in the Canada Day crowd.

No, how do you hold it still?

Find a better location for your tripod so it doesn't get kicked. http://www.walterpcalahan.com/Cheers/Fine_Art.html

I plan on shooting the FW from an old train bridge (now part of the walking trail system) and bracing the monopod on the 4 1/2 ft. high hand rails.
Would that give me enough support?

Have you considered a Joby Gorillapod (http://www.joby.com/products/gorillapod/slrzoom/)? I have one (the SLR Zoom version) and it can handle my Voigtlander Bessaflex and Takumar 200mm or my F80 with 70-300mm zoom no problem, I have even used it with my Bronica SQAi and that ain't no lightweight!. You can fix it to any available fixed point, and no-one would be in danger of kicking it.
The gorillapod comes without any kind of head, I found the addition of a cheap ballhead made it much more flexible.

Capital idea Andy.I think my local pro shop carries them.

Or you might also consider a tabletop tripod. Best fireworks I ever saw (and ever shot) were in Lucerne in 1983. I had just bought a Rollei SL2000 35mm camera in Munich, and it had a waist-level finder. I put the camera on the ground, mounted on a Leica tabletop tripod and ball head, looked down into the viewfinder, and opened the shutter when the fireworks started. When I had a few bursts on film, I would close the shutter and be ready for the next bursts.

I use a Manfrotto monopod that has extendable supports; the 560B monopod by Manfrotto. The monopod is equipped with three firm retractable feet at the bottom of its leg. Makes for a nice stable support with the space advantage of a monopod.

I like a monpod for shooting 35mm with long lens as I am able to shoot at slower shutter speeds, but I dont think a monpod will work for fireworks.

If you can find one with others not leaning on it, or walking on the supporting structure....

I have a large A clamp... the sort that I have littered around the studio space to hold flags, refectors etc. I have a 1/4 -20 stove bolt drilled into the back side, with a wing nut on it. You take the head off of a light weight tripod, and thread this thing onto the head.. Bingo. Camera support to go that fits into the tripod. It works well in zoos etc that als don't allow tripods. Zipp it all unassembled into the camera bag. Clamp it onto the pole that says don't feed the animals, etc, and you have a great steady platform to shoot from.

It is not quite as stable as bolting a tripod head onto a Manfrotto super clamp fitted with a 1/4-20 stud, but it is also about $80 cheaper.

I really don't think a monopod will work for that use. They're not designed to hold a camera fast for that long a time...too high a chance you'll have blurred shots.

Remember, the longer the exposure the higher your chance of a good burst will be, and the longer the colourful streaks will be, too. The gorilla pod thingy is a great idea, as is a small tripod.

I didn't have a problem with my Gitzo tripod on Canada day here.