Parts

Main body (sides/bottom)
Can be laser cut acrylic
Drums (smaller licker-in drum and large main drum)
Drums can be made from PVC/ABS pipe w/ acrylic end caps
Drums are covered in "carding cloth" which you can buy
Axles for each drum
Guide pegs/blocks
Keeps fibre from going beside the drum and wrapping around the axle
Pulleys and belt
Crank
Brush (for keeping light fibres in place)
Little rubber feet

Notes

First version will be crank-driven, can add a motor later if need be.
Distance between the two drums is controlled by a round insert with an offset hole for the licker-in axle, rotating this will move the two drums closer/further from each other.
Higher ratio between drums cards better but requires more crank revolutions for the same amount of carding.

Outstanding Questions

How will the drum spacing adjustment inserts be attached/made?
Static? How do deal w static?

Things to Purchase

PVC/ABS pipe
materials for: axels, belt?
carder cloth
little rubber feet?