KyozoKicks, a custom shoe designer featured recently in Official PlayStation Magazine (and before on Kotaku), intended to wear these Creeper Vans to Gamescom this week. Instead, as his PC up and died, he'll be selling them to raise money toward a new one.
Only one pair exists, and KyozoKicks doesn't plan on making more. They took a heck of a long time to do. ("The placement of each coloured square had to be considered so no colour was placed beside a square of the same colour on any of the four possible sides.") Still, "to bring an idea for a pair of shoes to life, for them to match what I had in your minds eye is a hugely satisfying experience."
No price is mentioned. If you're interested in buying them, or contributing to KyozoKicks's PC fund, contact him through the link.
[Update 2:28 p.m.] A Kotaku reader advises that it appears these shoes in question have already been sold, through an eBay auction in the UK.
Custom Minecraft Vans by KyozoKicks [KyozoKicks]