I ran across this site recently, and despite some spelling errors, it has an awesome collection of videogame console concept art and unreleased consoles. It’s worth it just to see what the SegaCD almost looked like.
I ran across this post on GamesRadar today, it’s got a killer collection of mega man art including ALL THE ORIGINAL BOSS ART. It’s totally nutso nerd-tarded (and I definitely downloaded everything to my desktop just now.) Are you geeking out yet?