I do also although I which it would be a lot more robust and flexible.Those darn colors that run out all too quickly...
you can use more than one, i.e. red, red blue, red blue green, red blue green yellow,
My mistake, I meant the fact that one can't create custom color tags, not that I can use multiple tags on a single file.
This goes into depth on how tags work and the problems that would happen with custom colors:
http://arstechnica.com/apple/2013/10/os-x-10-9/9/