Help, I have a landcruiser 2002 100 series TD, have a very strange noise coming

Hi there I have the above car and in the last two weeks noticed a strange noise coming from underneath.
The low down; I have worked out that it is a rotational noise as it comes on at different speeds and it is faster at higher speeds and so n so. Just before I heard the noise I had the tyres rotated (front to back) as there was a slight wear on the front LH tyre. I then went away up to the Murry camping and drove through a bit of bull dust.
Since I started hearing the noise I re-did the front and rear brakes, inspected the rear handbrake drums and adjusted them and still, the noise remains.
It seems to be apparent most often when I slightly release the accelerator when cruising, but can be notice when im at high speeds and at low speeds coming up to lights.

I did 50 km on the freeway today and before I hit traffic lights I stopped and checked the temp of each wheel bearing. No heat in any of them.

I feel like I can feel it in the steering wheel and have also as a passenger felt it resonating through the floor quite strongly.

What is this noise I ask, 3 mechanics are dumbfounded, two of them said wheel bearings, the other one and I don't agree.
Can anyone out there possibly offer an explanation? Has this happened to anyone else?

The noise is like a rub/light scrape sound, (like the noise of a leaf lightly scraping on the side of your car as you slowly go by) it is intermittent and is rotational.
Thanks, any comments or most will be most welcome.
Dave