There are eSATA Express34 cards available cheaply which support port multipliers like this one:
http://www.shopaddonics.com/itemdesc.asp?ic=AD5ESAPM%2DE&eq=&Tp=

That gives you five SATA drives which you can mount in a box of your choice. Power for five molex connectors and the above multiplier shouldn't be too complicated. Its all DC.