I just finished my first project from The Happy Hooker and naturally it had to be a Fat Bottom Bag. The yarn's Debbie Bliss Cotton DK. It's not been decorated as yet - I had a jewelled brooch in mind, but of course now I can't find it.
For the lining, I put some padding into the finished bag, then laid the fabric over the outside of the bag, pinned it where the darts should go and machine sewed about 1cm inside the pins to make it fit the inside. Seemed to work fairly well.