Maybe I'm becoming a bigger negative snob. 35's have the ability that I look for once in a while. But I love the bigger negatives, and wish I could find that capability in medium or large format
You can have that ability with a medium format SLR. Long lenses for medium format can get costly, but you seem to have a fair budget for photo equipment. If you also want autofocus occasionally, there are a few 645 systems that could suit your purposes.
Another option, if you want most-definitely-not-autofocus, would be to add a telephoto lens of around 400-500mm to your Wisner and a rollfilm back.
There are also some less costly options if that is a concern. I use a Bronica S2A system for 6x6 and have managed to put together an extensive kit with 40, 50, 75, 100 Leaf Shutter, 135, 200, 300, and 500mm lenses (plus a 240mm Heliar I use occasionally for portraits, half a dozen backs, and a few exotic accessories like a tilt-shift bellows) for less than the cost of an M7II with one or two lenses.