May be it's nice to watch... Accessories for the Sony NEX ...

The linked page for the MIG-SNX7B lists that item as compatible with the NEX-6 and 7, so perhaps that's the way to go if one doesn't mind the bulk. Personally I'd rather just carry a (much smaller) spare battery and swap when the time comes, but I can see the appeal of these grips too.  It looks to me like (from the pictures at least) you just use the little hatch in the battery door that you'd use for the AC adapter, so the door stays closed (with a little wire passing through the hatch).  If someone has one of these and would care to comment on its quality, it would be much appreciated.