Vantec NexStar 350UF 3.5" External HD Enclosure
 

Unlike the NexStar's 2.5 inch sibling, the increased power needs of a 3.5 inch drive requires the use of an external power supply. The power brick is not big, about as long as a CD Sleeve and is pretty lightweight. If we have to have 120V power to juice it, I would rather see a little larger enclosure with the converter built into it.



http://reviews.pimprig.com/miscellan..._enclosure.php

Some universities or colleges (we call in the U.S.) require external HDD enclusure for certain classes. Too bad, this may be what you look for if it had power converter..;)