This is pure speculation, but it sounds reasonable. (to my twisted mind)
I thought of this because the console has an extremely short power cord, and the two consoles known to exist were found around Chicago.
The power cord is less than a foot long. The perfect length to mount the unit in some sort of demonstration cabinet. The headquarters for World Book was in Chicago. During the years surrounding the copyright date on the games, 1989, the Consumer Electronics Show was also held in Chicago. Perhaps they made a few of these prototypes to demo at CES and when the show was over some World Book employees gained custody of them. The one I bought came with Golf and Sub Hunt as well as the TutorVision games, so it was known to the previous owner that it functioned as an Intellivion.
One other oddity, whenever you turn it on you are greeted with a bright colored solid screen. You have to press the reset switch to get the inserted game to start.
Thanks for all the congrats, my wife's find of a box of 5200 protos a few years was our previous best. I'm getting more exited about this as time passes. I had no idea how unique this was until I started searching for info.
-Chuck