"endorsements are usually paid for by the company or manufacturer either with free instruments or cash to the artist-- something a small builder cannot compete with"

I will gladly endorse any small-shop luthier's product for the piddling charge of one set of D'addario medium gauge PB guitar strings. A bargain endorsement if there ever was one! However, there is absolutely no guarantee that having my name associated with your product will in any way increase your sales. More likely, the opposite. But, ya never can tell. It's just possible that one of the six people in the world that think ole BWL is a decent picker (please ignore the 6000 who have yammered something about "Get off the stage!" through the years) might happen to wander into a music store and wanna buy the thing. Dunno. Probably a stupid idea. How about you send me a set of strings and I don't endorse your product?