I already have a set of the harley cans I picked up for $20 on the bayLooks good. Many people use the muffflers from a Harley as you can often find them for free at a dealer or $10 max each. Many Harley riders like louder pipes so these get replaced when new or almost brand new. They also show up on eBay but that's usually the more expensive route.
There are several companies that make exact reproduction mufflers for the C500 Standard and Deluxe, TAS gets them in from time to time as do many other places if you Google around a bit. Exact replacements for a Custom are next to impossible to find, I had to pay $235 to a place in the U.K. to get mine but they were dimensionally exact, very thick steel and have what appears to be a very professional, thick chrome job on them.