It occurs to me this is my first post. Been lurking too long I guess.

When you jack the car up to inspect, what car part are you resting on the jack stands? Maybe you're pushing things around by putting the weight of the car onto a component that is not supposed to support that kind of weight.

Also, if a local mechanic who has nothing in the game suggests something, pay attention. These guys can be soft spoken but have good hunches.

You feel it in your feet? Steering rack is there. Drive shaft is nearby.. I'm wondering if this is suspension, or something else?

Just a thought: For the price of web cams these days, how hard would it be to hook up a camera under the hood down low in the suspension pointed at different parts and take several test runs, recording the video to your laptop... to help look for the origin of the shake?

Cheers
Scott