.. but isn't it the the theory that's the problem with getting the JAA IR. From what I know, and as an FAA IR holder, there are some differences in the flying test but nothing that any reasonable person could object to.
I think it's more than that. The JAA IR flying training has to be conducted by a JAA approved school. The exam has to be conducted by a CAAFU examiner in a specially approved aircraft fitted with screens. The approvals mean that the number of places you can do the flying is limited, and the prices are therefore high.
AIUI, you can do an FAA IR in your own aircraft at the local airport. All you need is an instructor and some foggles. I'm not suggesting that the test is any easier -- from what I've heard I'll take the Nav exams over an FAA IR oral any day! -- but the logistics certainly are.