Finding a touchscreen display that would work with the existing chassis would be awesome!
I am planing to make a 15in sized 2 in 1 with a custom chassis from machined aluminum and 3d printed parts. For ports I am planing to place usb-c hubs between the motherboard and outside edge.
I also ran into the issue of very few display options and lenovo was one of the only brand that I could find replacement displays without buying the whole lid.
For this project [Project&Inquiry] Framework 2-in-1 there is interest in finding a 13in touchscreen display that can be made to work with the framework so you might want to keep an eye on that as well.