Another hobby of mine is pinball machines, and those have a similar weight-to-value problem when shipping long distances. Two frequent cost-effective shippers used in that world are Forward Air (has to be dropped off and picked up at a FA terminal, which is usually near an airport) and North American Van Lines (who will pick up and drop off.) Might give each of them a call. A lot of it is going to depend on how much effort your seller is willing to put forth in terms of boxing/wrapping, hauling to a shipper, etc.

Duncan