That is very cool Nick.
Brings back memories, though I was one for Motorola 68XX, 68HCXX and before that those very sexy Zilog's.
So I went straight to find a Zilog image, not a plain jane Z80 which I knew intimately, but they have a Z84C00.
Image is here http://visual6502.org/images/Z84C00/Z84C00_die_shot_20x_1b_1600w.jpg
I wonder if they have a signetics 2650 in their files?
Paul