What kind of replacement stock are you looking for? OEM? Composite? Solid walnut? There are numerous sources for aftermarket stocks for the M-700. If you want factory original, try calling Remington. Otherwise you can look at any of the following links (these are just a sampling of the more popular ones that come immediately to mind):

HS Precision
McMillian
Boyd's Gunstocks
Richard's Microfit Gunstocks
http://www.stockysstocks.com/
Bell & Carlson
Hogue
Choate

Any of the above each make a selection of stocks for the M-700, you just have to find one you like. As for the smaller than standard barrel taper, either you can just use one for a standard Remington taper and live with the slightly larger stock/barrel gap, or many of these stockmakers will custom inlet the barrel channel for your barrels taper. You just have to call them.

Mike