I’ve been tracking this one with great interest. From the description:

Up for sale is one of the rarest Apple computers you’ll find. This is a prototype/clear Macintosh Portable (M5126) backlit. I’ve been collecting for many years now and only know of four of these left in the world. All of which, based on my knowledge, exist in private collections i.e. Lonnie Mimm’s, an individual in Europe, this one, my personal collection. This is one of my favorite Apple computers and the fact this is a clear prototype make is unbelievably rare. The chances of one of these coming up for sale again are very low.

And:

The engineer I bought this from worked on the Macintosh Portable project. Another buddy of his, who also worked on the project and was leaving the Apple, said he planned on throwing this prototype out. The person I bought this from literally found it in his buddies trash before he left Apple. The engineer I bought this from kept it in his office until he left Apple and kept it safe for 28 years.

Follow the link, check out the pictures. Beautiful. From what I can tell, this is the prototype of this device, which Apple sold from 1989 to 1991 at the incredibly expensive price of $7,300 (about $14,000 in today’s dollars). Crazy.

As I write this, the prototype has a current bid of $8,100. Don’t tempt me, internet.