Small bag needs small, light notebook...

Well, I just bought a notepad from LV, its the note insert for the pocket agenda. It's a nice little book all on it's own, you don't have to put it in an agenda holder. I think it was around $17 or something like that.
 
They make a Mini Agenda, look on louisvuitton.com It looks just like my little Zippy Coin Purse but it had paper in it. My Zippy fits in my back pocket and the Mini Agenda is the same size.
 
LV makes a small notebook called the Carnet de Notes. The mono version retails for $305. It's a small refillable notebook and it comes with a pencil for jotting and one refill. The refills are a bit pricey though, but you might be able to find something similar at an office supply store instead of buying refills from LV.
 
Not LV, but Hermes makes a notebook called the Ulysee. It comes in several sizes and colors and start at around $135, refills start at $25 depending on the size and the purpose. It's a favorite of mine to keep to-do lists and jot down things on a whim.