I came across these custom made slip ons of Link and Zelda and couldn't help but notice how incredibly well painted these were. Not only that, who says both shoes have to be identical?? I found these on DeviantArt, and the artist is Bobsmade. This company is based in Germany and the owner is an amazing freelance artist. They not only do custom shoes, though the photos I will be showing in this post will be shoes, but they also do custom frames (wayfarer glasses), headphones, t-shirts, and a sh!t ton other things! (I'm currently in LOVE with these Avengers wayfarers)
Bobsmade also have their website where you can shop for current items or request a design for your item you want. I've seen Totoru designs, Harry Potter, Star Wars, and others. Really, you can do anything. Allow for up to 1 month to receive your custom item - I think it'll be worth it.
Check it out! Bobsmade.com
I've selected the geekiest custom made shoes I could find on their DA; I love all of these, especially the Captain America and Iron Man pair.