I read in the FAQ that there have been several requests for PoE and that the project is looking into it for future releases. I'm thinking though, since you are able to power the device via some of the GPIO pins wouldn't is be possible to just make a GPIO-add-on-board such as the ones listed in the WiKi (the Gert-board etc.) that will sit on top of the RasPi and simply do the PoE-feed.
I'm seeing something like this http://www.acceed.com/pdf_catalog/rayon ... atalog.pdf
could be "turned into" such an add-on. That would be a great add-on, probably fairly easy to put together for someone with a little electro-mechanical knowledge (and equipment).
I would be willing to fund development (to a certain extent). Anyone?