I was considering bumping the storage drives a pair of Sata IIIs up from 1tb to 2gb and then adding in a 2tb Sata II model as well for storing system images which will still leave the twin 1tb OS drives inplace while boosting the internel capacity. But the cost wasn't going to be worth it at the time since I was already paying out $110 for a Black edition 1tb drive. You might see $5 or so knocked at times at newegg.
A 3tb would be another thought while still not preferring the Green Power type drives there either. That would replace the 1tb which fills too fast when grabbing images from the laptops and a pair of desktops. That's using Acronis TI for the smaller image sizes(compresses image sizes down) for not only 7 but one Vista desktop and Vista laptop as well as a second 7 laptop plus the second 7 Pro mini tower.
Fortunately those do not see the larger volume of files ilke the main case does on a regular basis since the second case is a remote station for other projects as well as others not trying everything out as far as examining various apps and trying various things out along with working with video capturing. That can chew up drive space in a blink of an eye!
The docking station idea will work if you have several small drives or need to recover files from one without opening up the case to install it internally if not having an enclosure. You can stack drives to one side while working with others! You don't see those too often anymore however. When running a fast search EBay and amazon come up first. Amazon.com: 2.5" 3.5" SATA IDE HDD Docking Station Dual Hard Disk Drive Dock e-SATA Hub-red and black: Everything Else
Mainly this is due to the increasing popularity of usb/eSata external drives and enclosures seen in the last few years as well as larger capacity drives being available now that weren't seen let's say 6-7yrs. back. Plus not too many still use ide drives except for maintaining older pcs when needing a replacement. Most now look at either larger capacity, external, or SSDs and wouldn't even look at docking stations.