Re: Vehicles: We'll be adding multi-seated vehicles, but most likely not in the first release (to enable us to release sooner).
Re: Jedi Outcast co-op: As Sniper mentioned, you've got the wrong people. We've always been a Half-Life mod. The only other game we've seriously thought about converting was going to be a paid project, and was cancelled only because the deal went sour.
Mad Max: The first version of Sven Co-op for Half-Life 1 was released on the 19th of January, 1999. Check the HL release date in comparison to that

(and consider that the SDK was not available for some time after the game's release). Admittedly, that didn't include support for the SP storyline (this was added later)... but then, I was the only team member at that stage.
This comment was edited on Dec 4, 22:10.
Sven Viking