The magnetic whiteboard rig works great! I used that for my skull shirt back in October. That would make it easier to engrave a design on a larger textile/leather item like an apron.
It kind of seems like it would be less hassle to just cut out something as simple as an apron with conventional tools (e.g., scissors), though. Maybe a patchwork apron? Or make one out of interlocking modules like this bag. 