And the answer is............ (drumroll)....................... No.
I got a PM from Brent (BWaller) last week to say he'd bought one to try, and this is his words:
"I got that dohc 650 cooler, you're right it's a nice little cooler. The adaptor has the same diameter mating surfaces for the o-rings, but the large lug on the engine case (filter bolt attaches) interferes with the adaptor. The plate only comes within 4 or 5mm of the case, so I suppose the adaptor could be modded to work, but the inlet/outlet will be underneath at about the 4 o'clock/8 o'clock position. Without spending a lot of time I'd say it would be way easier using the "tried & trued type" you make."
Not trying to drum up business, just sayin'. Cheers, Terry.