Saturn Repair: Saturn shimmy/shake from 55-75 mph, shimmy shake, cv joints

Question
Thanks in advance for your time.  Looks like you have quite a fan base.  Anyway, I have a 1996 Saturn SL1.  I developed a shimmy/shake at the higher speeds a number of weeks ago.  I had the car looked at for repair.  The tires were rotated, two pulley tensioners were replaced, the plugs and plug wires were changed, transmission fluid and filter were replaced, brakes examined, CV joints and axles examined with no issues.  These basic repairs did not fix my problem.  Problem still exists, and appears to be getting worse.  I don't want to put to much more money into it, as I plan to replace it within 6 months or so.  Could you please list for me the "other" things it may be, like alignment, tire balancing, a transmission that is going bad(this is what the repair technician suspected it was for instance a problem with it going into overdrive?).  Anyway, other than what I described, there isn't a whole lot more to go on.  Acceleration doesn't seem to be an issue, there aren't any noises, it doesn't appear to be pulling to one side or the other, it doesn't appear to behave differently when I turn the wheel versus just leaving it straight.  It does do the shimmy in that speed range whether I am accelerating, or decelerating, as long as I am in that speed range.  The brakes don't seem to play a part in this either, as I don't feel that shimmy at the lower speeds.

Any help and direction you can offer is most appreciated.  Thanks again for your assistance.
Alan

Answer
Alan,
 Thank you for your extensive question.  You'll never believe how many times I get, "How do you replace a spark plug?"  
 Here we go.  A shimmy at highway speeds (68-75 MPH) usually indicates a tire out-of-balance issue.  A shimmy at slower speeds can indicate other things.  For instance:  if you filled a tire with air from an air compressor that has not been drained recently, water can enter the inside of the tire.  This causes a nasty shimmy at the speeds you describe.  You can also have a tire become "out of round" which could cause the shimmy as well.  My advise to you is to move the front tires to the back and see if the shimmy moves with it.  You should be able to tell right away.  If the shimmy goes to the back I would replace those two tires and be done with it.  Alignment, only under a few circumstances, will have something to do with the balance of a tire (this is most likely not your problem).  Your transmission causing a vibration at highway speeds is almost rediculous.  The repairs you listed lead me to believe that you took your vehicle to a Saturn facility for repair.  If your original concern was a shimmy at highway speeds, I would take it back to them.  I pride myself on fixing it right the first time....something they should do as well.  
-Before you take it back, make sure that there is no mud on the inside of the rim.  I have seen dried mud caked onto the inside of the rim cause a similar condition.  That's something the technician should've noticed seeing as how you had a 30K or 60K service done.  Anyway, let me know how this turns out.

Chris