I have found a number of FN Mausers, including a JC Higgins Model 50 and a Colt Coltsman for under $500.00 that could be the basis for a Whelen build. Since I have time, I believe I'll wait and keep looking for a Mauser custom build in .35 W on the auction sites before taking the plunge into building one of my own.
This is of no help to you, but this M98 Whelen just popped up FS here in Canada. Bit expensive as the stock would need to be swapped out. I personally knew the bbl maker and his 35cal bbls all shot well.
