Need some advice on intermittent vibration

[coheed]

So here's the deal. I have a vibration for the FIRST 5 minutes of driving between 45-50mph, then after 5-10 minutes of driving the vibration moves to 50-55mph, then 20-30 minutes in the vibration happens between 60-65mph, and the vibration gets smaller the longer I drive but doesn't go away.

I got new (to me) wheels less than 1500 miles ago. I had new tires put on them, and purchased hubcentric rings for them. And I relowered my coilovers when I put the wheels on. Had the alignment redone and everything is within factory spec. Since this has started (the last 200 miles), I have rechecked every torque spec for every bolt on my suspension, checked tire pressure twice a day, had the tire balance rechecked, and my alignment rechecked and can find nothing wrong with the car. The only thing I haven't really checked are the wheel bearings. I don't know what else to check or do about this. Any and all advice is welcome and appreciated.