When checking the prices in your area on craigslist remember these are the asking prices and not always what they sell for. Some are way out there and others are reasonable. One in my area is described as Mark V with attachments: Band Saws, Jointer, Planer, jig saw, band saw, extra blades, pulleys, drills, lathe chisels....too much to list individually. Over $16000 invested, most parts are still NIB. It is currently priced at $3400 and has a stock picture of a Mark V 520. It has been for sale on craigslist for over a year. To be realistic do not expect to make a big profit. Also you might consider selling the SPT's separate from the Mark 5. I have seen what I consider to be good buys sit for sale for a long time. There is a refurbished Mark 5 510R upgrade that has been for sale over a month in my area for $350.
I just sold two Shopsmith Model 10ER's last weekend and have a third 10E sold to be picked up today or tomorrow. These are totally restored Model 10's complete with everything they came with when new. I sold them at what I feel is a good price of about $300 which goes to help support my hobby of restoring old shopsmith's. I do not make a profit on these but enjoy working on them. Other Model 10's in the area have been priced between $45 to $900 for "as is" and not complete machines.
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.