How difficult is it to fit a Bisely frame to a Blackhawk?

Not difficult at all. The hard part is often finding the parts to do so. All you need is a grip frame and grips, trigger, hammer, etc.

Easy to do if swapping parts from another gun, but if you're buying the frame from Midway you'll have to do quite a bit of filing, sanding, etc. then polish/finish as they are by no means "drop-in" parts...

If you're dead set on the Bisley, that's one thing. But if you're simply looking to enhance the shootability of your plowhandle, you may also want to consider Jack Huntington's grip frame extension. Jack reshapes the standard Ruger Blackhawk grip to a more "Bisley-esque" shape. The new frame is then adorned with custom grips cut to fit your hands. There's an example of the transformation here.

FWIW

Jack has some good looking grips/ frames, any idea how much it cost for the mod and a set of grips?

About 200+ I believe. He did one for me but did some other stuff too. If you haven't already bought the parts I would go with Jack. Probably not too much different pricewise.

200$ doesn't sound that bad, for a grip that is useable. Was thinking a about a set of grips any way, just to get away from the rubber ones I have on it now. But if it would fit my hand also it would be that much better.

Any idea if you can just send the grip frame, I noticed that he's in californiastan.