Awesome, Nick! I'll be building along as well - I began gathering parts right after getting home from the party, so I was excited to hear from Ryan that you were working on one of these as well.
Thanks for the link to the ring sizers - I couldn't remember what size the prop used, and the set I ordered ended up starting at 14.9, instead of 14.5 (doh).
Mike mentioned that the piece between the ring sizer and the black collar was a coin cell battery on the original, and a piece of aluminum machined to a matching size on the duplicates. It looked like a CR2032 size to me...
As for the back button - it's from a Glo-toob Lithium flashlight. I only chanced upon it after a lot of searching because of the "splashproof" on the button.
It looks like the button was simply pressed into the extra acrylic tube section, with the knurls leaving those grooves in the plastic...
A couple of other things I heard mentioned while we were examining the prop:
- The motor is an expensive geared thing (Mike said they were $40ish apiece) that still spins freely when off, despite the gearing.
- The batteries are in the ribbed black section, but I didn't catch what kind
Here's an album that was linked to in an old RPF thread with photos of another of these: