Roger,
I have a fella making these for my Remmy rolling block in 38-55. I bought this rifle on the EE and as it turned out, it was a project! My friend did a full re-build on it including making a new extractor, new pins, new button, new firing pin, bushing the block and re drilling for the new firing pin, honing the receiver to precisely accept the new pins, setting back the barrel and re-chambering then rust blueing everything. It was worthy of a new stock!!!
I can ask my friend if he wants to take on another project. Problem is he's a fussy-arse and would probably want your rifle to fit everything. Unless you can do the final fitting/finishing. Having said that, your rifle sounds a lot like mine with a Green Mountain heavy hex barrel and maybe he can work from mine.