Toyota Repair: 94 Camry Shakes, wheel bearings, ball joints

Question
Ted,

I have a 94 Camry that has developed a shake recently. The shake is felt through the floor and seat, not steering wheel.  It shakes on acceleration only and seems to smooth out at 80ish.  Dont really feel it in 1st or 2nd gear not matter what rpm.  But feel it very bad accerating in 4th or 5th gear around 50 - 75 mph.

I have read similar posts that point to inner CVJoints.  So I have changed both axels complete with joints - no change.  I have also installed 4 new tires - balanced, had the alignment checked and corrected, replaced the top motor mount (dog bone), inspected lower transmission mount and it looks OK to me  - Car has never been in accident and runs great. I have changed all fluids, brakes, belts, timing belt, hoses.  All ball joints, wheel bearings seem tight.  Diff fluid has been changed and is proper level.

Could it be clutch or differential?  

Answer
I don't think the clutch or differential could be causing this, you have done just about everything there is to do to correct the problem, don't believe I can be of much help on this it's one of those situations where I would have to drive the car to try to diagnose it, have you tried having a toyota dealer diagnose it? If so, what was their recommendation.