Adam -
You mentioned something about paralleling capacitors. There's a good concise theory-discussion here (for those interested):
http://www.oz.net/~coilgun/theory/capacitors2.htm
Mouser part numbers TVA-1906, TVA-1907, TVA-1908 are 20mf, 30mf, and 40mf, respectively, 500V, genuine Sprague, good choices, but are physically large and aren't cheap. But are top-quality units.
I recently tried these Cornell-Dubilier snap-mounts with good results. They're 1/3 the size and 1/3 the price, but they seem to work at least in the short term. I don't have any long-term results to give an opinion, but the quality seems acceptable.
http://www.mouser.com/search/Product...5985-85-500V47
You have to be a little more creative installing them (the snap-mounts are for PCB's, not hand-wired chassis). But I found with clever wiring, they do stack and hide in old multicap cans very well.
Here are some 100mfs:
http://www.mouser.com/search/Refine....uf&N=1323038+0
Not currently in stock though, so you'd probably have to call.