There's a demand for them, from $25 to $2500 depending on what you make and who you are. Real nice ones forged and engraved with some inlays and fancy work will usually go for $250 and up depending on how high art they are. Forged will always command more than a prettied up, customized cast head. But like rifles, the name and reputation, well-earned, contribute a great deal to the price a pipe hawk will command. If Hershel made it, etc.
A guy comes out of nowhere, makes a beautiful rifle, well carved and engraved, that gets notice at Dixon's, etc, and finds he can sell it for $1800-$2500 tops. 6-8 rifles later, if he continues to do terrific work and his work has a style that works for people, the rifles will be going for $2500 to $4000. If 10 rifles later he's seen as the next coming of (insert your favorite big name maker here) then he may reach the place where his rifles start at $4000 and just go up from there. But that first one, that sold for $2000, may be every bit as desirable as the rest.
Same would be true for a smith who makes fine hawks. Most of the money makers have also paid their dues on the show circuit. Folks will pay more for something from a guy who's well-known.