I just found this!
https://github.com/steam-deck-controller/steam-deck-controller
Looks like a project to basically cram the steam Deck components into a 3dprinted shell - but it isn't finished yet!
There's a proof of concept video in there where it's shown connected to a PC with a standard USB ribbon pinned to a 2.0 A head... Might have to give it a go someday!