I don't think so. WebOS is a valuable asset and HP definitely want to keep it to themselves.

We'll see =).

I don't think they care if they keep it to themselves or not so long as they have a fair amount of control over it. They've been bitten in the past being tied to a 3rd party for improvements to their mobile OS and want to avoid that. If WebOS hadn't gone up for sale, they would likely have used Android

webOS is already very open. It's basically a linux kernel with a few binary drivers for the radios, and there really isn't a need to hack on those.

The most valuable things in WebOS are the GUI and UX design, not the kernel or drivers.

I'm interested to see what they came up with in tablet form.

People had been doing some pretty nifty stuff even before the native SDK for webOS came out so I'm not sure what you mean by open sourcing it. Among the various platforms they are probably the most open and their developer tools are light years ahead of anything the competition has to offer.