What about TempDB, an archive, and a spare? 10 Drives doesn't seem to be enough even if TempDB is on DAS (which would mess with clustering if you went that way).
To answer your question (apologies, I ask another question), what are you shooting for with your SAN? Max capacity with the ability to rebuild bad drives in an online fashion? Max speed (which can usually be done MUCH better by writing good code)? Max safety? or ???
--Jeff Moden
Change is inevitable... Change for the better is not.