How to swizzle a class method on iOS?
Turns out, I wasn't far away. This implementation works for me:
void SwizzleClassMethod(Class c, SEL orig, SEL new) {
Method origMethod = class_getClassMethod(c, orig);
Method newMethod = class_getClassMethod(c, new);
c = object_getClass((id)c);
if(class_addMethod(c, orig, method_getImplementation(newMethod), method_getTypeEncoding(newMethod)))
class_replaceMethod(c, new, method_getImplementation(origMethod), method_getTypeEncoding(origMethod));
else
method_exchangeImplementations(origMethod, newMethod);
}