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!