If you are on the AtariAge Intellivision forums, contact the members TrekMD ( https://forums.atariage.com/profile/15527-trekmd ), and Intellivisions Digital Fanzine (a.k.a. ZillaRush) ( https://forums.atariage.com/profile/43234-intellivisions-digital-fanzine ).
I've previously helped TrekMd with a few homebrew Intellivision game manuals, he's really good at making them.
And, ZillaRush has made some killer box art and overlays for some recent Intellivision homebrew games. Again, really great stuff.
I myself have made quite a few overlays and box art that folks have really liked, but they're usually quite futuristic looking. ZillaRush's stuff looks like real vintage Intellivision overlays and box art :)