Adam Myerson at Cycle-Smart runs the only camp I'm aware of. And that was cut back to a single day last year. There are a lot of full day clinics but unfortunately I'm unaware of any camps. (I seem to vaguely recall an ad for a camp but it was mainly a road build for 'cross and not a skill specific camp)
We had some kids at our clinic last year. One of them would invariably fall over when one of us would talk too long. It was pretty funny.