There's a zombie unit here that you could always just paint the .dds file white yourself if need be; http://forums.civfanatics.com/showthread.php?t=525542
Just an idea if you're needing something quickly.
Right I already have the ice golem zombie, but we want a true walker at some point. And one with a sword or lance. By the way that zombie. Do you know what animations that unit uses? Never mind it uses Jaguar warrior.