hey hn!
I am a 15 builder, i am currently working on a 3d printer which turns into a suitcase, this is the prototype cad model at this moment - i am working on the physcial version. It's a cartesian type printer which uses rails and rods gantries. It uses telescopic rails and hinges to be able to be folded. It's open-sources on github, you should really check out the repo :)