Don't forget - storage costs, unless you have room for 70 new bikes with assorted parts, wheels...etc.

I think this only makes sense (and for less money) for a shop (or big time flipper) local to this guy who can pick them up in a van and has the storage space and time to sell them slowly.

How would you like to be the guy responsible for shipping and organizing these on a group buy? With 70 bikes you're bound to have a problem with a couple - resulting in fighting and hard feelings. It'll be a TON of work and you'd have to deal with grief and distrust.