Now any plush impostor can pose as the "16 Bit Plumber"! This was a request by my 4yr old daughter as she was getting tired of her American Doll's face!
My daughter wanted to carve and color her doll's face but I paid so much for that stinking thing I just couldn't let her do it... So to compromise we designed a Mario mask to her doll's face scale and fixed a scrunchy hair tie to the mask for perfect fitment. Now she likes her doll again and I kinda do too.
This one is easy if you have access to a 3D printer, go to: http://www.123dapp.com/skp-3D-Model/16BitPlumberMask/603173 , download the 123D file, open it in the free 123D app, size to your liking/print bed, export to a .stl file, slice with your preferred gcode creating software and print your own "16 Bit Plumber Mask". Drill holes in the temple for your choice of mounting string and you can use a Sharpie to color in the eyebrows and mustache to your liking.
I printed this in ~2hrs using no support material for doll fitment at my daughters request; see uploaded images for actual output.