You did not say what kind of tires you have. The description you offer indicates tire problems. I would suggest that you go to: www.gsp9700.com and find the machine near you. This machine can analyze your tires for excessive road force variation (stiff spots.) It is the next step for your situation.
Driveshaft vibration usually is at its worst under acceleration and is at a much higher frequency than tire vibration.
Best of luck,