I would be more interested in understanding how nestopia will handle the xml inside the zip.

I mean: I assume at start it will support .nes images (to be crc'ed as a whole file minus the header) and use the board & prg & chr info (and the pins at a deeper level) to correctly emulate the game.

but, looking in perspective, wouldn't be better to add hashes to prg & chr in the minimalistic approach as well... on the long term, it would be nice to add support for splitted sets without force the user to edit each xml files...

my 2 cents