Well, I've broken down and have arranged for Turnbull Restorations to supply me with a bigger hammer. As a starting piece, I located a newly made Winchester 1886 Takedown with the pistol grip stock and crescent buttplate. It will now get the full treatment. After thinking about it, I've settled on the following:

Cal. 50-110
Barrel: 24" full octagon takedown, 1-26 twist
Full magazine
Restocked with a nice piece or NZ grown European walnut I bought from Geoff Slee 15 years ago. Will have it made up into a Deluxe style shotgun butt with period correct Winchester recoil pad and grip cap.

I'm going to have them also refinish the factory stock to have the correct colour and chequering. That way I'll have the option to switching back to a more traditional look as I wish.

I'm also going to do the hammer/tang safety conversion, so it is no longer rebounding and uses the traditional safety half-cock. The tang safety will be removed and welded up.
Everything will then be finished, case hardened and blued.

Now I need to be patient and let them do there work. Hope to have her towards the end of the year so I can see how she does on those tough NT buffalo.