There is a new listing for a 1973 Midship on the auction block at the Chesapeake Bay Maritime Museum in St. Michaels, MD. (cbmm.org).  Go to the Features area, find the Donate or Buy A Boat and click on that.  The Midship is down very the bottom when you get to the boats going up for auction on Labor Day Weekend.  They have it listed for $2,900 and it looks clean by the photos.  Wheel steering and an outboard for power, it also includes 4 sails.  One would have to contact the museum to find out the hull number.
I thought people might find this to be of interest.

Elk River

My wife and I stopped by the Maritime Museum and found out that the boat is still located at the Oxford Boat Yard.  We stopped by there to view it.  It is hull #106, built in Dec. '73.  It needs a rub-rail, interior wood refinished, and the hull on the port side is really chewed up where a raised outboard engine apparenly did a number on it (not real deep, but certainly ugly looking).  The keel will need a fair amount of work, also.  The turnbuckles look original, too.  The wheel steering and outboard cables are running loose in the aft cabin, not hidden at all.  It will probably go for a pretty cheap price at the auction should anyone have any interest. It will be a very inexpensive way for someone to have a nice boat after some elbow grease is applied.

Elk River