You might be surprised what they will pay. Talk to the designers and architects. Ordinary old gunsmucks like what hang out here are not going to be buying these. The folks that buy the guns from Seacoast will stand in line for you work.
Build one of these guns so it can be fully disassembled for easy shipping. Get a pretty girl in a bikini with pirate bandana and a linstock and take a picture with hee behind the gun. Put the picture up here first---we want to make sure you get the picture layout right. Then put one of these guns up for sale on EBay and see where it goes.
Houston use to have all those home decorating and builder shows. Make yourself some business cards and a port folio of pictures of the different guns you have built go to the show and look for the architects and designers who build the fancy home and offices, Visit with them. Show them what you can do, no pretty girl pictures here. Don't try to sell them a finished gun. Sell them your skills and even offer to work with them on specualtion. Don't build to sell, sell to build.
I would guess you could get at least $1500 for these and probably more. If the designers or architect, don't tell them a price, just say you can build to fithis budget. But tell them no if they try to low ball you.