uefi_multiboot: Create UEFI-compatible boot drive supporting multiple ISO images.
It requires UEFI-based target systems, and Ubuntu-system to build, and a disposable USB drive (everything on drive will be deleted).
https://github.com/sundarnagarajan/uefi_multiboot
(Someone looking to create a script that generates a UEFI boot drive could also benefit from using parts of this script.)