You would be after an external model then. They do not produce as good a picture as the internal ones, but if you're looking for the flexibility aspect of it, external is the way to go.
There's a chap in the Atari community that is working on releasing an external FF/SD for Amiga and his name is Roy. Last I spoke with him, he was having trouble with noise with PAL modes. This was back in July last year. Anyway, if you want his e-mail, PM me. I'm going to write him now and see where things are sitting...
Other than his affordable box which hopefully will be available soon ($65 IIRC), there are models in the +/-$100 range on ePay designed for gaming consoles that some have reported work well.