About 10 years ago someone was selling an LC prototype case. I remember wishing I had the money for it. It was transparent green and pink. It had two floppy drive slots. It didn't include the motherboard, which would have been pretty cool. An LC with two floppies.

Here're a few more pictures, this one is of a prototype MacPro that was also sold on eBay. It has a bunch of diagnostic LEDs on the motherboard for the various components. They flash different colors depending on what they're doing, with identifiers written on the PCBs next to the LEDs. I originally posted it on MacNN, and the actual owner posted some additional interesting information on the unit: