The source code for all of the open components is posted - I think I linked it elsewhere. There are some closed source pieces from third parties that they can't provide source code for, including their own media player (which supports Windows Media) and the Adobe Flash Player.
Most of the important partitions on the NAND Flash are signed with Sony's key, so they'd have to publish their private keys, which doesn't seem like something we could expect Sony to do.
It's probably possible to create an unlocked firmware release without those components, the device wouldn't be able to do very much. It would take substantial effort to bring some replacement for the UI pieces to get it even close to what it did, and it's not clear anyone would seriously step up to do it.
I have the resources to do *some* of that - after all, we did some of the original development for the dash device - but even I don't maintain a build system, and just the part I'm doing - replacing the Control Panel, themes, and music subsystem is a *lot* of work.
I will be releasing sufficient information to run software on the device without requiring server authorization for anyone skilled enough to write their own software. We'll see if anyone will put their time and effort into actually doing so besides me.
I will be using that ability to release software to connect to and use the chumby backend systems to provide chumby-like services. If someone wants to do something else with the device, they are totally welcome to create their own alternatives to my offering, as long as the rights of both chumby and the third parties that produce the chumby apps are respected.