Fwiw, what we've done at my company for some of those sets of data that just aren't *worthy* of being put on a Netapp, is we've also picked up some SNAP servers. They're basically a cheaper lower-end version of Netapps. (A *lot* cheaper, unfortunately, as now I often have to defend why we need to upgrade the netapp rather than "just buy a few more SNAP servers".) They don't seem to scale nearly as well as the netapps in terms of performance when there are many concurrent users, but for lower-end storage we've been fairly successful with them so far.
http://www.snapappliance.com/ http://www.snapappliance.com/
I think there are several of these low-end appliance solutions on the market now. Snap is just the one we've had experience with here.