Thanks chaps, that's all interesting stuff. The X-E1 can be had at quite a good price at the moment, no doubt because it's an old model, but I'm guessing the differences between the first generation X-Trans models are just wrapping. Or at least that's how it looks from reviews online. I see also that they've got a $200 rebate on the XF lenses until Christmas
Has anyone tried using a battery adapter? The fake battery shell draws power from an external power source, which sounds useful for AP.