This topic came up during a side conversation today at Brad's lighting workshop. I've downloaded and played around with the
Knowledge Tree document management system. This is not set up for a photog's image processing workflow, but I guess something could be scripted to work together with Photoshop, etc. We were actually discussing it as a method of keeping track of model release forms and the like. No reason you can't use it to keep track of actual images, but most people already have something for the purpose that works better. There are other places in a photog's professional life where this sort of thing might come in handy. For example, when I was playing with it I partially set up a workflow for mail-in rebates. You could use it for invoices, registrations, all kinds of things, but to be worth the hassle of setting up and running something like this you'd need a pretty good volume and/or a strong desire to tinker.
Just wanted to make this available to all.