I want to add a NAS network drive to my Airport Extreme (802.11n) base station. I'm looking for one that is remote accessible over the Internet (without special services that cost $), and that shows up simply as a drive in Finder (and Windows Explorer on my PC). Every candidate so far has limitations. The most suitable seems the LaCie Ethernet Disk Mini ($180 at Amazon for 500 GB), but it has high power consumption even when not active. Any suggestions?