San Francisco Bay Area Mechanical Keyboard Meetup 2018
2018-11-10 just came back from today's Nor Cal keyboard meetup, and from a friend's house.
TGR Alice Keyboard
i saw several of this today

they are extremely heavy. You'd have a hard time holding it with 1 hand. The keyboard case/frame is some kinda heavy steel.
it's called TGR Alice keyboard see reddit
the layout is similar to LZ Ergo Keyboard. 2017
see also this heavy brick keyboard
and Brick Heavy AEK64SS Apple Keyboard
iris keyboard is fly weight!

i also saw several Iris Keyboard. it's extremely light. Like, weights just a bunch of keycaps. very nice. The thumb position is also nice for small hands. (unlike that of Ergodox Keyboard ) though, too few keys for me. But would work if coupled with a 30+ keys Programable Keypad
Keyboardio serial number 0001 for sale!
also saw Keyboardio serial number 0001 for sale today. asking for $300. i tried it, it's nice.
it's this one if you want to buy https://i.imgur.com/j6BKVDy.jpg
See also: Keyboardio Model 1
trackball that spins
found this one today. The trackball spins! Never seen any actual trackball that can spin.

looks like this site sells the raw material http://www.devlin.co.uk/products/input-devices/defence/
(2018-11-10 thanks to plebtheturtle)
The closest i've seen is a trackball prototype, see Trackballs That Can Spin
more photos
here's photos, by plebtheturtle NorCal /r/MK Meetup 2018 album
reddit: reddit