John - Thanks for the info!
I am waiting for a call, form the Beta dealer in Maine, to get a price, just in case. I believe the Yanmar comes with all of the needed parts, as well, but I will double check. The price on the 3YM20 was about the same as your Beta quote!!($6900 in Nova Scotia, and in Maine, as the dollar is about even)
As far as installation, with both the Yanmar 3YM20 and the Beta BD722, I could use my existing engine bed / front mount positions, and would have move my rear mounts back 2-3".
I have decided to only repower if we find problems with the old 2GM, which will require putting more than a few hundred bucks into it!