Where on earth did you get these? Because this doesn't sound like something i can hop on ebay right now and buy for a few bucks shipped.

Those are amazing.

And remember prototypes are one thing into showing you possible differences that the game could have had.

But the original art work in the designing area shows you exactly what was going through their heads from the very start on where they felt they wanted to take this.
I mean could imagine if he had one that did not show tails on the cover of sonic 2? Leading to the idea that they didn't even think about adding a secondary character in the game.