There are a ton of small circuses still around but they seem to be predominantly in Europe. A friend of mine,
Scotty Walsh just
got accepted into a circus that performs from Memorial Day to Labor Day at the Trocadero Theater in Elitch Gardens. I think it's much easier to run away with the circus in other countries.
I know he auditioned for the spot using a fifteen minute act he's been working on for the last four years. Also, if you get into a circus as a Rousty I imagine you hear about a lot more open clowning positions.
The possibly more difficult option might be to start your own circus by joining up with like minded circus entrepreneurs! There are a million Cirque de Soliel companies now, but there are far less companies doing anything like the stuff from the olden days.