Obviously with datadir=C:... I can chance the directory bitcoin uses. I would like to store my wallet on a different hard drive than the blockchain. Is there a command for that?
I don't think you can make bitcoin core look for the wallet.dat file outside of the specified data directory, but I think you can make a symbolic link called wallet.dat in the data directory and have it connected to the actual file on another drive. You can find info on how to do that here:
http://www.howtogeek.com/howto/16226/complete-guide-to-symbolic-links-symlinks-on-windows-or-linux/