I've got to say, completely ripping off a good aftermarket LS1 head designed for the smaller bores, moving only the head bolts, oil drains and coolant ports to match the L6 block would be a awfully attractive product to me, and wouldn't require as much development. It's easy to drop 2 grand into a lump ported stocker. I think 2500 is your price target.

"The first rule of overkill: You can never have too much overkill."
"Overkill is underrated."