Drobo + Time Capsule I have a Time Capsule that I use for Time Machine, and am thinking about getting a regular entry level 4 slot Drobo to hang off its USB port as shared, non-Time Machine disk space.  The Drobo appeals to me because I can expand it as my needs grow, and because it has RAID-type functionality built in.  I figured that I could also unhook it from the Time Capsule and attach it to an individual machine should the need arise.

Have you tried this before?  How has it worked out for you?

Edit: Just to clarify, I was not looking to use it for Time Machine data.  The Time Capsule itself has plenty of disk space for my Time Machine backups.  I'm looking to add network based storage for general use (archiving videos, rarely used disc images, etc.)  I don't really need the performance of a Drobo FS, so I was looking to see if I could save some money with a regular Drobo.
I've plugged in a Drobo S into the USB port on an Airport Extreme when I needed fast and dirty file sharing. It worked fine. It was only for a week, but I didn't notice any sort of unusual behavior. 

Once you've done the initial setup/config via the Drobo interface, the drive acts just as standard USB drive. It's not the fastest thing in the world, but you're limited by the USB 2 anyways, so your experience regarding speed will depend more on your actual usage.