Tom Talley, who you can read about on Memory Alpha, has decided to auction a bunch of items he collected while working as a construction and location foreman on Star Trek. You can see Tom's auctions here. Tom is a really nice guy and his stuff has pretty solid provenance. In addition Star Trek Prop, Costume & Auction Forum member Chrissy is designing a nice COA for all these items.
I recommend you check out Tom's auctions and bookmark his list as he has more stuff to come!