Bruce, here is another one that might fit the bill.
Built by George Britnell. Maybe you could talk him out of it?
Gil
George's engine would be lovely (all his creations are) but it appears to be high revving with a very high stall.
Keep in mind that George's engine is fairly new at this filming and not likely broken in yet. A good break-in and a small work load would likely allow for slower running. That said, you are aware that an engine with a .9" flywheel would need to be pretty will seasoned to run slowly.