does anybody know if an A500 external rf modulator module works on the back of an A1200
That's an odd question I'm sure few people have asked and it makes me curious. The A1200 has a sort of built-in A520, so probably nobody bothered to try a real A520 on it. Hmmm... my first thought is that the A1200 monitor connector is different than the one on the A500 where the A520 plugs in. I'm not sure, though. I seem to remember the A1200 (mine at least) coming with a special adapter so you could connect pre-A1200 monitors.
Someone else would need to clarify or confirm these off-the cuff ideas, though.