I've done some instruction on a [link=http://www.horizonhobby.com/products/super-cub-lp-bnf-HBZ7380]Hobby Zone BNF Cub[/link] and found it to be a good trainer. It's small and slow enough to be flown in a park, and I was really impressed with how well it worked as a trainer. I think this one should be seriously considered.

Hogflyer