2006 Lexus GS 300 Hit Curb, slight vibration in steering wh

I hit the right front wheel on a curb at 5-10mph causing a scrape to my rim while making a turn. Afterwards, I notice that the steering wheel was vibrating slightly by feeling it but I could not see it vibrate. So, I got the right front wheel rebalanced and got all 4 of my wheels rotated and rebalanced. This resulted in the rim and tire that I hit to be placed in the rear on left side. I still felt vibration, but it was not as bad as before. I also noticed my car was pulling left or right on uneven road, so I got the 4 wheel alignment, and now it is fine. However, I still get slight vibration through my steering wheel and floor at times when driving on certain roads ranging from highways at 70-80 mph to city roads at 45-55mph. It is so minor but its still there. I told my Lexus dealer about this and the mechanic took the car out with me to duplicate the problem, but he couldn't since the it comes on certain roads and doesn't on other roads. It never used to do this. Sometimes it there the whole time on a certain highway or comes and goes. Mechanic told me it may be due to one of the tire being cupping but I told him it can't be since I felt it after I hit the curb and the the wheel I hit is now in the rear, so the problem has to be located in the right front region. Do you think it may be a more deeper problem? Such as wheel bearing damage, control arm, etc? I am not sure what to do next, since the dealer says everything is fine, but I doubt they even looked at the components of the right front wheel.