In Paris, this department store called galleria lafayette had CUSTOMISED HAVAIANAS! Super cool, a must-buy! here's a piccie of mine! I chose the colour of the base and straps and where to put the little swarovski crystals and my name :).
I found this one on some random site :)
You can make this: click here.
Also, googled up customised havi's and found this site that sells heaps of variety of havi's: here