Just noticed a couple days ago that at about 65mph the car feels like i'm running over a rough road. At about 68-9mph the vibration stops. It doesn't start vibrating until 65 so there's no gradual increase in vibration, it just starts immediately. Could it be the driveshaft?

 

id try getting your tires balenced befor i went that far

 

What your describing sounds like a classic case of Torque Convertor Clutch shuttering when it applies. That can easily be misdiagnosed for other driveline problems. Check the ATF to see if it's good and at the right level. Anything behind the transmission and the balance of the tires is usually relative to vehicle speed and will increase as you go faster, not go away. You discribing a vibration that ONLY occurs then seems to be that. Look up other stuff here for the TCC, tons on how to deal with it.