So he owns all of those copies just to play multiplayer? That's dedication. I believe the 4-player cables were released with a game called F1-Race or something, but few were produced. How can you get 15 GBA cables connected and working with an original Game Boy?
Also, am I to understand that you, UncleBob, use The Cober Project to print out scans of the boxes and create your own covers for games? So you don't actually have 13 complete copies of FaceBall 2000?
I know Faceball 2000 is awesome but I don't think it has any monetary value. It's a shame, that.