As Dusty said they all look to be in very good condition. The belt sander looks like it may benefit from a little rehab or TLC. I did notice from the serial number/vent plate that it was originally a Mark V with the original table system (AKA 500) made before the Mark V 510 came out and was factory upgraded. That still makes it a Mark V 510 as long as it has the floating tables and connecting tubes/accessories. I agree that if you sell them separately you will expand your group of buyers. Some Shopsmith owners may need only one Single Purpose Tool, like a bandsaw, where other buyers may only be looking for a Mark V to get started. As for what to sell them for that is hard to say. The more complete each item is the more value it has since the buyer doesn't have to replace missing parts. Looking at what they are selling for locally doesn't mean that is what they sold for. Of course you can accept a lower price from an interested buyer.
Mark V 520 S/N 09-11-01 completely upgraded to Mark 7, with all SPT's & more.
Model 10ER S/N R64000 first one I restored on bench w/ Shopsmith metal ends & retractable casters. Has Speed Changer, Model 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E S/N 1077 oldest one I have restored. On bench w/ Shopsmith metal ends & retractable casters.