Hey Todd,
If you're into a DIY project, check out a small trailer kit from Harbor Freight. I put one together back in 2008 and it's been to 2-3 TBFs. Build your own platform and sides, very lightweight, rides in slipstream and not very expensive. Go for the larger wheels because of interstate duty.
As for parking, we've parked ours along the road headed east and there's spaces in carhenge on the west side where you can back an attached trailer onto grass.
Anything, that sounds both like a fun project I'd get into, and a better scenario than renting every year. I'll look into those. Off the top of your head do you know how much the trailers weigh? We'd be pulling it with a Prius, and I think the towing capacity is only about 3,000lb. I've already been meaning to start a trailer project for hauling our tractor, so why not build a wee trailer for festival!
Listening to:
Gillian Welch on repeat