Well, I didn't think my buzz-saw-bomber-plane-daytona500-loudest-at-45mph noise was tires, but I had to rule them out. The Delaware weather finally warmed up enough to allow me to do that in the Delmarva Power parking lot. (Remember I'm in the process of moving, and don't have my garage or tools).

There's nothing visibly wrong from underneath, but I did notice a shiny nut on the flex-disk, indicating the prior owner had some repair work done. Maybe the noise is driveshaft related, but I've never heard a roller bearing go like that, and a u-joint would probably make clunking noises.

I'll have Horst Fischer (shop was recommended somewhere, but it looks like his shop is behind his old house) look at it on Thursday and hopefully the suspense will be over.