Me too, got five old Zeds at the moment.. current project is putting a tuned GPz750 engine in a 650 frame, with modern wheels, forks, brakes etc.
One of my projects which I’ll get found to soon (honest!) is a GPz750 frame which will have a zr7 engine and electrics, with a 2007 GSXR750 front and rear end. The engine won’t be tuned initially but will run vm29ss carbs off a slab side GSXR750.