2002 Elantra with 180,000 km highway driving...

Here's the problem but my dealer and another garage have yet to solve the
problem. I'm getting tired of paying to try things without a solution in
sight...

- steering wheel wobbles at lower speeds
- at higher speeds it's a vibration
- sometimes pulls to the left sometimes slightly to the right.. sometimes
not at all.

Here's what's been tried so far:

- Tie rod ends needed changing (Possibly unrelated)
- Several allignments (thankfully i didn't have to pay for all of them)
- Several tire balancings
- 4 new tires.. problem went away for a few weeks but is back again
- Re-balance made no difference

I suggested the rims may be the problem but i've been told several times
that the balancing would sort that out... but balancing is really the fix
if it was only a high speed issue right?

Any ideas or suggestions?