So a couple of months ago, after seeing Funk-Station's computer bag reworking of the classic blue IKEA bag, I wondered if you couldn't tweak it into a diaper bag, too. It has three separate pockets and both hand and shoulder straps--though the current Ikea bags don't have the very handy snaptab closures of the vintage ones. The base and the leftover fabric are the exact same size, and changing pad-shaped. It seemed like Destiny.
Sure enough, after I picked it apart, my mom stitched it together in about ten minutes. I would totally use this next winter.
howto photoset: The 59 cent Ikea diaper bag and changing pad [flickr]