Actually you could probably argue that there is no software sale on eBay which returns anything to the developer/publisher. There is one PowerSeller in particular who makes an elaborate song and dance about legal/non-pirate/will prosecute/everything guaranteed etc. but only sells OEM software...
AutoCad auctions suffer the same fate as Region 2's example above, with total illogicality from eBay regarding where the ax drops. I guess any product which retails at £3,700 and can be bought on eBay at £30 is liable to attract the more colourful buyers/sellers....
Some sellers (Search = Autocad on ebay.co.uk) have resorted to setting up one-bid-wins auctions with a couple of hours lead-time so everything is done and dusted before eBay UK wakes up and snips them out - you have to admire them; sort of; the sellers I mean.