Bearings are here!!
This is how they interface to the driven gear (prototype here)
I’m 3D printing the bearing housings right now
And the rims are here:
Aside from the part about, you know, designing them and printing them. I’m definitely looking forward to cracking a beer tomorrow night and designing rims 
Over the weekend my goal is to make the inner and outer plates and actually put a full gearbox together. Probably I’ll make the plates out of a sheet of PVC rather than commit to aluminum.
Still outstanding are the truck mounts. They are completely designed in my head but I hope to have them sitting on the table by Sunday night.
Also, bad news, I ordered the wrong thickness of aluminum for the plates. I meant to order 0.200 but I accidentally ordered 0.250, which is too thick (and surprisingly heavy). I know how it happened, I went back to the website to check my order and I noticed the price, per sheet for 8" by 7" for the .250 is $11, and for .200 is $26, so my little brain chose the right price but the wrong size 
Now I have to decide if I’m just going to use them or if I’m going to try to mill them down, which is not really a strong suit of my particular machine. But given enough time it could do it; so still noodling. I could go with 0.125 which I have lots of, but it seems like it would be too flimsy.