My 3rd generation 1 TB Time Capsule hard drive has bit the dust it seems. Not found by the Airport Utility, making some grim sounding death clicks. Giving it a bit of thought, I'm thinking my options ...

So this problem ended up being a dead HDD. The Genius replaced it under warranty, and we were fortunate to have very recent backup on our networked Time Capsule, so we Restored from the last backup ...