Looks good to me.

IMO, by going through the import/export interfaces and using the Item abstraction (which I don't think is really necessary) the code becomes unnecessarily rigid, and I liked that about my previous approach better, but this is more consistent with your previous code, so that's positive. In any case, that's just to provide an opinion, this approach should work fine and it's mostly a matter of taste I suppose.

This seems good enough to merge, so let's.