My website is a photographer website, so it is base on pictures, a lot of pictures. And selling them it is different than selling things, because you sell many times the same thing: a photo, just with various dimensions, way of being printed,... .
Here is the way I use market press: http://www.ombres-et-lumieres.eu/store/products/
And here is the way a shop for photos is organized: http://www.ombres-et-lumieres.eu/vente-de-tirages-2/
The main part is done in the admin: I can make bulk upload, decide this upload are photos to sell, and gave them their main price properties. It also make a search to find the keywords of the photos and add them in a keyword panel in the admin.
I 'm not a pluggin développer but have enough skills to make a part of the work ( and some is yet done). So if someone is interested in making that kind of add on, it would be great.
Why I don't want to use the one inline? because something went wrong with the "purchase panel" and as it is a freeware (https://wordpress.org/plugins/sell-media/), I don't have help. But the main reason is that I prefer to have something more integrated, in both levels, the one of the "shop" plugin and the one of "where the plugins come from", for compatibility reasons.