Would be interesting to see what turned up mate, I personally can't see many taking the time to work it backwards though when like ya said they can just cross X and X and end up with another strain of X, I don't know what goes into a proper breeding programme but a few years back when I did speak to someone who made their own strain they made it sound very complicated and time consuming back crossing and them cubing etc for desired traits.
On a side note I tried that livers cross cheese the other day that I was going to get some cuts of and was very dissapointed with the smoke, it tasted ok like cheese with a possible hint of livers but nothing more and the smoke really didn't compare to either the Exo or the livers, was more on the Exo side but seemed to be lacking in the buzz and flavour, I had a fat joint an within half hour or so felt totally sober after a very mild buzz, I was as polite as I could be and turned the cuts down simply because I don't think it would encourage repeat business I mean it would sell all day long but it wouldn't do very well in repeat because you could smoke so much of it due to the extremely short life of the buzz which is amongst if not the mildest I've ever had, a gram wouldn't keep a smoker happy f