Shopsmiths have their fans, but its a small group and they have a poor reputation outside of that fanbase, although I know people do speak fairly well of the lathe attachment. I think you will find it a very difficult item to move in the current market at almost any price, unfortunately. It is an item where someone with dedicated machinery is unlikely to want to dedicate the substantial floorspace to a shopsmith but a new prospective woodworker who might utilize multiple tools on one probably is going to be gunshy about it, and even more afraid to tackle a rusty tool.
Same for the radial arm saw. Much like the shopsmith they have their fans... but it's a rather small group, and there are many, many, many old radial arm saws out there at next to nothing pricing.