Nevermind.. looks like the issue was a bad connection and the drives not seating properly in the console. Took them out and seated one without the case to make sure it was making a connection and it shows up!
OK.. I've got to be doing something wrong here... it's not like this is rocket science ;(
I've got a Star Wars edition XBOX 360 that the 320GB drive died on (clicking noise... yay). I happened to have several WD drives around the house (WD3200BEKT - Sep. 2013, WD2500BEKT - Nov. 2010...