Studio Cult sells a large enamel pin in glorious effigy of MS Paint for $18.
3" x 2 5/8" metal alloy with 3 pins on reverse side
Thickness varies from 2mm – 3mm
28 soft enamel colors
Silk screen button elements
Laser engraved menu text
Large screen enamel protected by an epoxy layer
You can even use dry erase marker on it!
There's a Photoshop version too.