BOM is now in the "Files" section with links, will be adding to it as I get some sorted out (the keyboard)
The size could be reduced by at least a third if we remove the plugs and jacks entirely in favor of soldering directly to the PCBs, but it then requires quite a bit of delicate work with any mistakes being rather costly. I choose to just remove the top two USB jacks (carefully) with nippers.
I rather keep the project easy and have it be a bit thicker. It's still plausible because there are makeup palettes with stackable trays: http://www.sephora.com/color-wonderland-eyeshadow-palette-P412573 (the small makeup you might have seen in a purse are compacts, different thing).
Using the Pi Zero is also an option but processing power and usability
would take a significant hit. The Raspberry Pi 3 is, for most purposes a
fully functional computer and generally as quick as a low end laptop
for any reasonable tasks. I didn't really want to sacrifice that.
The Raspberry Pi 3 has on board WiFi but in order to do wireless
Penetration Testing a card must be able to go into monitor mode and do
packet injections- the WiFi chip in the Pi cant do this. So I'm using a
RT3070 compatible adapter.
I only skimmed the instructions, so you may have already done this, but are the individual makeup pots capacitive buttons? Then you could initiate different types of scans, etc, without having to reveal the keyboard.