I also don't like the SUB pickguard that much (I mean the diamond plate one). I could not choose the finish of my SUB5 since that was a special deal, and the solution I found for replacement of this pickguard is : NO pickguard. Looks very fine that way.
I have a black SUB. I replace the diamond plate PG with a white on from EB customer surface. It looks awesome on a black SUB - makes the instrument less "chezzy" than that thin, paper+aluminum diamond plate thing that passes as a PG.
P.S. If I had a white SUB, I would put a tortoise shell PG on it.