Money isn't an issue. Conflicting touring schedules aren't an issue. Musical genre isn't an issue.
Who is the one artist/band you would absolutely love to see closing out the main stage for one night over anyone else?
I've got to go with Daft Punk. They're poised for an epic comeback with the new Tron soundtrack and I still have yet to see them live. Whether they would still be touring with the same pyramid from the last tour or a new setup, something about seeing them on the main stage at the Gorge would make for a damn near religious experience for me.
I bet if Modest Mouse did a set promising something like LCW or TIALDFSWNTTA in it's entirety or just a set full of pre-good news in general, I could see them getting away with a headlining spot. Maybe even a 3 hour set if Brock promises to get shit-faced (looolzzzz).
Anyway, you woulda asked me this a year ago, I woulda said Pavement, so I guess it's all just downhill from here.
How about a supergroup with a member from each band that has headlined past Sasquatches. That promises awesomeness, awfulness, and hilarity all in one package.