Tom, I'm sort of with Glenn. I know its been done, don't see why or how.
I see that you have a 2x3 Graflok back in hand, which is a large part of the battle. They're hard to find and expensive.
When I had a 2x3 Pressman I took its back off and tried to fit my 2x3 Pacemaker Speed Graphics' back to the Pressman. Short answer, the two bodies' dimensions differed so a back for back swap wasn't possible. I b'lieve that the 2x3 Busches with Grafloks that I've seen on eBay had the Grafloks attached to a thin panel that attached to the cameras' bodies.
There's no disputing tastes, so I won't advise you to give up on your Busches, get a pair of 2x3 Graphics (one Speed, one Crown or Century), and not look back. But that does seem the easier course. When I had mine, I was greatly frustrated by the difficulty of finding lensboards.