I randomly stumbled across this on Facebook thanks to sponsored posts. Normally they're annoying and useless, but once in a while a good one pops up. This counts as such. A random t-shirt website has created 49ers-themed superhero t-shirts.
I can't vouch for the site nor the quality of the t-shirt material, so you'll want to do some googling, but the concept is pretty cool. They take pictures of various superheros and give them a 49ers look. The Hulk one pictured above might be my favorite of the group. Of course, Iron Man is the most natural fit given his existing colors.
Anyway, here are some links if you want to check them out. Again, I'm not sure of the t-shirt quality, but it's certainly a cool idea.