Husky without a doubt there are some who would pay to have the upgraded cabinetry. BUT I don't think there would be enough to sustain a viable business addition. Many of the folks who would be customers will live too far from you to bring it by. Many more of them will not be interested in install their own that you have shipped. Then there is the measuring problem. An amateur is bound to get something wrong, and along come the headaches to you when they complain that something doesn't fit.
The kitchen sink base cabinet unit is the most likely IMHO to be sold. Perhaps a mail order unit could be figured out on it but I just dont know what volume to even guess.
Go to this link and see what another cabinet man on these forums did for himself. (look at all his cabinet photos)
I think Sneakinup did a whale of a design and build out . I might order same if there were instructions enough to do the reface upfit by a peudo-novice. However if I was going to make the shell look that good I would want the innards improved too. maybe a turntable and more of a vermin proofed cabinet area. The latter would be a nightmare of design due to the open floor under cabinet for water pump and freshwater tank drain valves etc, not to mention the under counter furnace being tucked in there also.