This is not a new request. I think that the whole issue is just not being presented.
The way that PhotoShelter and a few of the other pricier individual stock selling sites are set up enables the photographer to spend his or her time photographing and not spending a lot of time setting up and tracking price lists and making spread sheets.
What everyone asks for is the ability to sell stock, and as many Zenfolio techs have replied all you need to do is set it up as a download and price it.
I think that the real question is, when will the ability to automatically sell images as stock that is automatically priced according to industry standards be available?
Thomas Mangelsen, as well as Art Wolfe use PhotoShelter to sell stock even though their own sites are content rich/dense. The software and pricing are industry standard.
So, the question is not when will the ability to sell photos as stock be available but when will the service be automated so that the photog can focus on photography and not setting up pricelists.
This, by the way is one of the selling points of these sites.