I did some more searching and found out that the originator of the bonecrusher-Larry Dahlberg, actually has a web page with a message board. I posted my question about the fly there and got this response via email from the man himself:
Actually the bonecrusher is more of a concept than a pattern.
I got the idea while watching bones struggle to locate flies after they’d come to rest on the bottom, only to pick them up again when they moved, then lose them again when they stopped.
I was reminded of the first plastic worms, which sank and laid flat on the bottom versus the later creation of the floating worm. Fisherman quickly learned that a floating worm with lead weight at its nose was visible to the fish from a greater distance and also easier to pick up. It all but replaced all other designs.
The vertical profile can be applied to any combination of fur and feathers. It is my experience that any pattern tied this way catches more bones and permit than standard designs.
I use a Gamakatsu 15R hook-size six to as big as I can get away with.
**(optional) bend hook shank appx 1/8” behind eye on size 4 hook at 15 degrees toward point.)
Secure lead eyes that are wide enough and heavy enough to keep hook upright about 1/8” behind hook eye.. Do not use so much lead it scares the fish. Best to have range to fish various depths and maintain desired sink speed. Place eyes on hook so point rides up. Best to locate hook underside of eyes and just ahead of bend (if you bent the hook) for stability.
Make body of Flashabou Dubbing with brass wire dubbing loop from rear of fly. Start midway in bend of hook.
Tie in 4 strands of fluorescent tipped Flashabou Legs (they are buoyant) Cut brightly colored tips so they are no longer than 1/4”. Secure to hook leaving legs 1-2” long depending on size of fly so two point forward and two point backward.
Use wing made of either wool of Fuzzy Fiber just slightly shorter than legs.
Tie facing forward.
Wrap legs and wing with thread (like a parachute style dryfly) so they stand vertical.
It’s usually best to match the fly to the bottom color.
It really works. Try it in a glass. Then try it in the ocean.
In testing it I have let it lie motionless where I knew bones would swim by and watched them go out of their way 6 feet to pick it up, even though it was absolutely motionless the entire time! I could not repeat that with any of the other flies I tried, and you can believe me that I tried ever tried and true traditional.
The bonecrusher is not so much a pattern as it is a different fuselage option.
Good luck, hope this helps. I’m really busy for the next few months, but maybe I can post some photos at a later date if this info is insufficient.
I found a pic of the a fly at orvis.com in their fly catalog, but it doesn't really look much like he's describing...