So I have a little insight as my mom actually works for ShurTape or "The Duck People" as a production planner and she knows all about what is up and coming. When she first found out about the new licensing a few years ago with "Hello Kitty" she asked about Disney. My understanding was that the response was it is hard for them to get the agreement to use the characters. I do believe that I just saw Spiderman at WalMart, so my guess is hopefully Mickey is not too far away. But it is also business. It might have been cheaper to get Spiderman's likeness and be able to produce duck tape at a cheap cost and sell for reasonable price ($4ish a roll) versus paying a lot for Mickey and having to hike up prices from $4 a roll to $8 a roll to cover the difference.Hope that helps at giving you a better understanding as to why its not out yet.
Also, did you think of using a white duck tape base, stickers and a clear packing/ duck tape cover? Same kid of effect, but you can personalize it a little bit more