Very speculative stuff. Valve mentioned ages ago they refer to their internal builds as 1.5, 2 and so on. I think Gabe even mentioned in an article late last year that Source 2 wasn't underway.
I would love it to be true, but it's not really Valve's way.
New tools are definitely in the works, though. Gabe has said as much, and the Portal 2 editor, and Source Filmmaker are, I think, great examples of where they're headed. I'm thinking a proper real-time editor, with the engine actually running inside it, and a new Qt UI, like they've done with the Filmmaker.