I was wondering about the cross class possibilities.
It seems as if the prestige classes are just the progression of their respective basic jedi classes, e.a. guardian->marauder, sentinal-> watchman, and so on.
Or is there information that says otherwise?
About the Yoda. Since we're talking D20 system here, you should talk a look at the Star Wars roleplaying books. Yoda is the top of the food chain really, together with the likes of Darth Sidious and Exar Kun. Vader and Mace come close, but aren't quite there. Yoda's true strength did not lie in 1 to 1 combat though.