This one from Jeffs Outfitters doesn't look too bad and wouldn't cause the bank to notify the IRS on the transaction.
Would need the base modified from octagon to round for your application .
Looks like one standing and 2 folding leafs.
Maybe it's junk,,I don't know,,never had one in hand. Just something I came accross one time.

http://www.jeffsoutfitters.com/SIT1035_Express_Sights_3_leaf.aspx?productid=113&categoryid=67