I'm probably going to be the lone dissenter here, but I think you're trying to make a silk purse out of a sow's ear.
The PSL is a fun gun, I have two, one original style, and 1 truck gun, with the square cut receiver that I picked up from WW.
However, having said that, I think the free-floated barrel, fluting, heavy barrel, piston set-up and the bipod attachment are all GREAT ideas, but in my opinion, you're going to price yourself out of the market for a gun that still shoots 7.62x54r.
Figure even a rock bottom PSL goes for $500, add in the custom made barrel, the gas system, and all the other modifications, and I'm guessing you're looking at anywhere from a $1000-$2000 rifle, depending on how much profit/return you are looking to get.
But then again, if they actually become as accurate as the Dragunov once the mods are made, I can see them selling too...
I want to see how things turn out and find out what the final pricing is going to look like.