RE: Has this happened to you?
First off Awesome bear. And with Trad gear to boot. You are the man.
Like others have said and your saying you'll do head up there and ask to see the hide. If he doesn't have it ask him where it is and explain you want to see it. the tanery should not have it. I dosn't take 8 years. If he tells you it will be done in a month then he's not saying the tanery hasn't returned it to him yet. Over 5-6 months at a tanery I'd be asking questions if I were the taxi. I took my whitetail to a taxi this year and he said 3 months at the tanery. Another friend of mine traps. he sends a bunch and they take a while. Not eight years though. His got it or he doesn't. If he recently sent it to the tanery I can see it still being there but he would have known by now if they had lost it 7 years ago. He's hiding something.
I'm hoping its there and he's realy just not done with it because of doing deer heads. I don't know what else he'd have to to but who knows. Either case I'd pay him a vist. And its sounds like you have enough family and friends to effect his business by telling everyone the story. That pulls alot of weight when your talking about that kind of business.
Keep us informed man.