Christopher - please tell us (OK, tell me) more about your air conditioning setup. I won't have a bus for a couple of years so I'm in no hurry. But I am certainly curious about how you're going about this. Might be best to start another thread about it, though, so folks can find it later.
I'm thinking my budget will permit a five-gallon bucket, a fountain pump, some straw, and a computer fan. But I would love to check out other options.