Hi Christine,
I'm not aware of anything exactly like what you describe, but I do have some possible workarounds for you.
First, the
Pirate's League specializes in giving guests pirate makeovers. There are also face-painting stations in all of the theme parks that may offer some pirate-like facial decorations. There are also pirate costume accessories (swords, eye patches, bandanas) sold in some of the shops, particularly the shop at the exit to the Pirates of the Caribbean ride.
As for the photo, Mickey and Minnie themselves are pretty easy to find in the parks, as well as at some character dining experiences. Grab a copy of the free Times Guide when you enter the park for all the details.
If you're talking about a cartoon illustration of Mickey and Minnie being added to your picture, that may be possible also. There are some PhotoPass photographers who can add Disney character images to the pictures they take of you. Sometimes M&M are one of the options. For details on all of this you may want to head over to the independent website stitchkingdom.com. Search there for the "Definitive Guide" to Disney's PhotoPass Service. This will give you the complete scoop on adding Disney characters to your pictures.
Good luck in getting your picture replicated. I LOVE your idea!