Wow. Lots of great info in this thread - thanks so much to everyone for sharing your suggestions. I picked up a used Prior 4WD from Mudbone and I'll most likely mount my Burton Race plates to it to try it out initially. I'll also be tweaking my stance a little next time I go up, and bringing the E Deck with me to give it a go.
I'm still hoping that a Nidecker Proto will show up for sale...but I ain't gonna hold my breath. Maybe I'll be able to catch one at the end of the season.
I'm also doing more research / thinking about whether or not I have the right bindings in my possession to match what I want these boards to do.
Now, if only it would snow...