Perhaps most surprisingly, all the designs aren't solely comprised of pictures of dicks. Somebody has immediately done this though. Well done, internet.
In a post on the official forums, Garry Newman revealed that he'd thrown together a tutorial for the first bit of workshop integration for head-meets-rock survival simulation Rust. It lets you put your own design on the game's t-shirts with a simple skin replacement and he used the Facepunch logo as his example.
It's some basic first steps for community mods that doesn't allow for a massive amount of change yet, but more complex options "will be coming down the line." Presumably it's only a certain amount of time until every rock is replaced by Thomas The Tank Engine and you can play as a dinosaur if you want.
The best the community has managed so far is this cut-out smiley face that leaves your nipples looking like eyes. A bunch of other designs have already made it online and expect many more in the coming days.
Garry's looking for feedback in the thread.