Is it worth it?
Do the majority of livebearer-buyers care where their fish come from? I would bet those that do care, would also care about the genetic integrity of the stock. It's easy to raise livebearers, but not as easy to raise quality (not inbred) fish ... while dealing with all the other fish store work. Going one step further, do the people who care about genetic integrity and the source of their fish even care about the guarantee?
Basically, I think they would need to be some pretty awesome livebearers to sell them at prices high enough to make up for all the cost (space, utilities, manpower) required to raise them to saleable size. They would need to appeal to more discerning aquarists than the "my-first-ten-gallon" crowd.
Just some thoughts,