hey sorry to hear about your situation. i checked my stock and couldn't come up with anything. if it helps the yanmar part number for a complete assembly is 724772-11700 and sould run $2746.97 give or take 10 percent.
Thanks guys. I have a posting at yanmarhelp.com as well. I think for now I will go with repairing the head I have, while I continue hunting for a used one. Let me know if you have any other leads.
Try Hoye tractor, they sell cylinder heads for YM2000 tractors, the price is about 600$, it's a replica off the 2TR16 head whitch is used on 2QM20.
Michael