From what research I've been able to pull together, there is some consensus that the 35 Whelen and 400 Whelen were concieved by the late Col. Townsend Whelen in 1922 ( 2 years after A.O. Niedner's 25-06 and a full year before the .270 ) ... and the first rifle in this "widcat" caliber was reportedly built for him by his cronies at Griffin & Howe.
The 7600 was first chambered for the 35 Whelen in 1988, and discontinued some number of years later, but I don't see any reference to the 7600's in 358 Win. Over the years, Grice Wholesale ( a large Pennsylvania concern) has commissioned Remington to build various "Special Run" firearms, including 7600's in 6mm Rem., 25-06, 7mm-o8, 280 Rem, 300 Savage, 35 Rem. and 35 Whelen, just to name a few, but again, no reference to any in 358 Win.
The last Special Run of 35 Whelen's I saw were in a Carbine version ... Epps had a few a year or so ago ... now long sold-out. "Whelen B" picked one of the last ones up as I recall.