I have four 1 TB SATA drives and want to use a couple of them as external drives. I have a Western Digital Elements external drive and really like two features it has:

1. It automatically spins down the drive after being idle for a length of time (don't know the length exactly)
2. It automatically powers off when the computer is turned off and/or when it is unplugged from the computer.

Are there any "bring your own drive" enclosures out there that will do this? If so, can anyone recommend one?