For those who are looking for one more protection of their format shifted files plus a fairly portable file sevrer then you might check out the Netgear SC101.
http://www.netgear.com/Products/Storage/NetworkStorage/SC101.aspx
It is capable of holding two ATA IDE drives and is very small for mobile use. It connects to a router and files can be shared along your network. Netgear software has to be installed on each PC that wishes to access the files on it. This is because the SC101 formats hard disks differently than a PC does. You cannot swap disks between a SC101 and a PC: the data will be unreadable.
It is not a cure-all security to keep your files form being copied or stolen but unless they have the software on any PC they try to put the files onto, the drives (and files) will be useless to them. I use two 500GB drives in one of these for archiving files at home. I have not used this case for shows. For shows I use the TeraBox II which holds four 750GB IDE drives (you can put up to 4 IDE drives of any size that you want). I use it with a mixer/amp combo and a laptop for an ultra mobile show. You can see more info about the Terabox II here:
http://www.ymiusa.com/product.aspx?prodid=466&catid=273
The Terabox is USB and can be plugged into any PC with a open USB port. 3TB of mobile file storage should fill anyone's needs. I have had zero problems accessing the enclosure for music or mp3+g's at the same time when using it with clubDJ pro 2.
Just a couple of options for those looking for external storage options for their mobiles. Both enclosures are very small and very mobile for quick setups and teardowns...
Tig