I’m facing a slightly different set of choices for 36er upgrade(s). I ride similar terrain as described above, but occasionally push to more difficult off-road trails and steep(er) downhills. My goals are a lighter wheel and better brake (currently have a v-brake).
The two main options I’m considering aren’t listed in the OP, but you might keep them in mind:
1) New lighter tire that’s supposedly going to be available soon. I took a look at the one Nurse Ben is running, and it may be a really attractive option. The tread isn’t ideal for road use, but probably a good compromise for mixed riding. Weight is the main potential advantage. However, I’m going to wait to see how they get priced and how easy they are to obtain before deciding for sure.
2) Nimbus Oracle 36. Although admittedly not a great choice if you’re actually avoiding having a brake. I’m also disinclined to buy one with the default aluminum spindle - very much hoping they give an option of the Oregon (steel) hub.
I’ve currently got a Big One with aluminum frame (solid and light - diferent than the one you had?), Coker Non-Skid tire (heavy) and 29er tube (similar weight and waaay cheaper than a fancy 36er tube), KH seat/handle (perfect, nothing to change here), and 152mm cranks. 165/137 cranks might be nice if I want to do more off-road, but overall I’m very happy with the 152’s.
My best budget upgrade option is probably to just try the new tire on my current setup. The Oregon hub is heavy, so might cancel out the benefits of other upgrades. And my v-brake is fine for road and moderate xc use (i.e. probably what I should limit myself to anyway).
My new custom uni option is to buy an Oracle frame with a wheel built on an Oregon hub, then separately buy the new tire and disc brake of my choice, and use my current seat and handle. It’ll be interesting to see how that would price out compared to buying a complete new Oracle with standard spec’s.