1.
Not done yet (if ever), but I think this would be eye-catching with iMac G3 400 Mhz SE (that has clear (with little blue) plastic):
- Take CRT-tube away. (know what you are doing, electrical shock risk!, even with power off)
- Take picture that is taken where ctr-tube screen should cover whole your picture on place where you put iMac for eye-catching.
- Put CRT-tube back.
- Put that picture to Finder desktop-background.
- So only Finder needed for eye-catching...ok iMac G3 400 Mhz SE looks still cool even switched off

2.
Modern eye-catching is look like retro:
- put 256-color grayscale colors to Finder (if somebody know how to put 2 color-mode in MacOS9, let me know)
- So only Finder needed for eye-catching, again.