I have the Sena folio. There's a pocket that I saw described as big enough to fit a checkbook. The pocket runs the full width of the inside cover and is a few inches deep, so if your notepad isn't as wide as the iPad, you can slip it right in. It also has business card slots (four of them), which one could also use for credit cards, and it has a clear ID slot.
Why the Hell anyone would carry their credit cards and driver's license in their iPad case is beyond me, but I'm sure people like that exist. I sure wouldn't carry all my eggs in one basket like that.
No, I don't work for Sena, I'm just really impressed with this folio. It's fairly expensive though. I spent $80+ on it at the Apple store.