Hey Bruce!...I was able to score a quantity of 4 for $80 shipped, or $20 each (ebay make an offer)I have an offer in for 4 more at $18 each but that has not been accepted yet so I may have found the bottom.
I am collecting them as I plan to mount several in a row on a wood board and gang them all to gather to make a power plant....not sure how big my gang will be yet 
Do these have any appreciable power Ben ? You could use a Wilesco transmission to "gang" them up.
When you get rid of the bearing rub issue they make a little power, not a great deal of it. The adjustable speed stirling I got with my last order with glass displacer easily makes twice as much power. But I like the all metal construction and the rather vintage look, I can lightly touch the belt pulley with my finger and it will slow the engine but not stop it so there is Something there!
I thought to do a Wilesco Transmission like you spoke of, if I get a paint color combo I like, may try Navy Blue base/flywheel with black power cylinder and cooling fins.
Thought it might look cool to have about 8 of them in a neat row about 1/2" spacing...likely need a 3rd bearing tower on the transmission. Then would like to put maybe one street lamp over each engine. Like to mount each with 2 knurled nuts counterbore from bottom of board so I can take any engine off line to service or run solo without tools required to remove. These are one of the few engines I can afford to have 8 copys of on hand!