I earned two hats on a site, and I think it would be great if we can wear both at the same time.
Can this please be made possible?
Sorry, I'm going to status-declined this idea just because layering that many images on a gravatar isn't really feasible for us -- not without severely sacrificing performance.
That said, there's a fairly easy "cheat" around this -- just screencap your gravatar wearing a hat, make that image your gravatar, and equip a different hat. repeat until you are wearing all the hats! (If you do this, I suggest using the version of profile page!)
If this was real life, you could definitely wear multiple hats! However, these hats at stackexchange are huge, so only one at a time!