There already is one.
Now what were those Obz's current project?
Aliens
Project Georgia (new IP and Sega)
??????
I don't think that NWN2's expansion pack should count as third. It even isn't even named in style of "main projects" aka Project NX1 (Neverwinte Expansion 1 I guess).
Since Aliens and PG are multiplatform games that third one SHOULD be "pure pc" one. Aliens = PC and consoles, PG = Consoles, X = PC
However, I haven't heard that PG would be console only, so it is possible Obsidian doesn't always follow their "rules".
Now, what I'm trying to say is that there is small possibilty Obz might be working on K3. Very small, but still.
LA "won't leave KotOR franchise behind"
OE wants to do K3
Particular part of this newest rumor.
Now, mostly that rumor is just typical "bla bla bla my friend of friend who works in industry knows bla bla comes to xbox bla for this christmas bla BUY THIS MAGAZINE TO KNOW MORE".
However:
Now, whole fact they didn't deny its existence doesn't mean anything, thanks to NDA. However, I guess that latter part could be called as sort of a slip.
Why there would be more information coming up about something that does not exist?