Basically, I'm looking for Lightroom for iPad :) but until then, I'm trying to find an alternative.
To organize and tag pictures I'll be using Photosmith which integrates with Lightroom.
Now, I need an app to do basic editing of pictures (cropping, exposure, saturation). But I need an app will do this in a non-destructive way and that will make the edits available as XMP so that later, I can just copy the XMP as sidecar files and load them in Lightroom (or better, it could load them via a lightroom plug-in the same way Photosmith works).
PS: I posted the same question on photo.stackexchange.com, see here.