The 12" iBook is very different from the 15" Powerbook. Most notably it's much smaller, smaller than a sheet of A4 paper. So having a sleeve with the ability to contain paper didn't make sense for the iBag. Which made creating the bag much simpler. In fact, we completely changed and simplified the design because of that. The iBook is inserted into the bag on its short side and there is no big flap at all, just two short pieces that are velcroed shut once the iBook is inside. Very simple.
As a fabric for the outside and the inside we used a dark-grey cordurouy but no extra padding in the middle. This seemed like the best compromise to keep the bag reasonably thin while being soft and feeling good.