Can someone recommend a mild RD longbow about 64" and doesn't stack at 31" dl?  Thanks in advance ESP

There are a number but you'd be hard pressed to do better than a Toelke Whip.

A number of builders of mild r/d longbows, but at 31 inches, I think most will stack pretty good.  Why not consider a 66- or even 68-inch bow?

Dan recommends his Whip for that draw length.
I apologize for lack of clarity.

I have used a 66" RD longbow before, but it was very limiting for my style of hunting.   Thanks for all the responses, you folks a very helpful. 

ESP

Not knowing your experience in trad archery and longbows, coupla things come to mind. 

The first is, are you sure of your 31" draw length?  Even a tall, big archer such as Howard Hill had a 28" draw length.  As most trad archers continue their shooting experience, at least a fair number will shorten their draw length - for better shooting and not for being overbowed.

If you really absolutely do require that long a draw length, even a specialty 64" longbow will more than likely not be as consistently stable as much longer 68" or so longbow.

Please tell us more about how a 31" draw length is yer requirement.