It must be a pain, but as Fender3x says, there's a good chance of getting a L/H custom version ordered of some of the kits, especially if it's a symmetrical shape (strictly speaking SGs aren't symmetrical as the top horn is a bit longer than the bottom horn, a carry-over from double cut LP specials). But an ES-1(ES-335 style) body can easily be drilled for L/H controls and bridge slant and a L/H nut fitted.
The problem for PBG holding a lot of L/H stock is (IIRC) that the minimum run order for a type is for 100 guitars, so if you had a L/H version of most of the kits, that's a lot of extra stock to carry and store which is going to take roughly 10 times as long to sell as R/H models. Of course it could be a chicken and egg situation, as if there isn't the stock, then people aren't even considering asking about other L/H model versions. Email Pit Bull and ask.