Carol, here are several, fairly extensive sites you might be able to find music at, or at least information on the trad. music of European circuses. It all looks pretty interesting and, in fact, I found an important site which I think warrants its own thread, too, so I will be double-posting it. It is the first one, though probably not as relevant for your purposes as some of the others:

Worldwide Internet Music Resources INCREDIBLE!!!

some info on circus music

an off-shoot of the first one; over 300 listings with links.

LOTS of Circus Links if you scroll down. This one looks as though it might be really helpful.

Hope this helps,

kat