As for a custom seat, I dont know. But see allot fo nice seat covers on ebay land.
If your foam is good. I have done a few before. Take the old off, usually pull out a ton of staples. and I use the shorter staples in a staple gun to apply the seat cover.
I prefer to use 3m super 77. I spray it on the foam and put the seat cover on, some stretching and jocking required.
the spray is a sticky glue spray, that sticks the seat cover to the foam. prevents the seat cover from lifting and looking bad.
vegas jeff, only pics of his work is on banshee headquaters, which you have to sign up for to see the pics,
nicest custom covers i've seen.............
They quoted me a seat cover, bar pad and fork boots for (I think) was $125 shipped. The fork boots were the neoprene slider type, seat cover and bar pad was from matching vinyl with custom silk screen printing. I come from 3 wheelers and over on 3wheelerworld.com their reputation is impeccable. From what little dealing I had with them, I can say first rate customer service.