Just got back from the Apple Store in Plano, TX, and I have answers. According to a Genius, the shortage has nothing to do with a refresh, and everything to do with the USB Power Adapter for the iPhone 3G that Apple just recalled.
Apparently, Apple has been planning this recall for a while now, and this particular Apple store already had replacement 8Gb iPhones packaged with new USB power adapters. He even showed me the box for the new 8Gb iPhones that had just arrived yesterday...there was a little green circlular sticker on the back of the box to denote that it included the newly designed USB adapters, and not the faulty recalled ones.
So for all you hold-outs thinking 32Gb phone will arrive this Tuesday, the smart money is on not seeing a refresh of the iPhones until after Christmas. Sorry to be the bearer of bad news.