Mysterious front end noise

First off, please forgive me for I have sinned, but I have my reasons. First, I think will get better answers from you guys since I haven't gotten much so far froom the first forum I'm in, and second, it is fairly similar in the front of a Taurus. I'm asking about a problem I am having on my 95, 3.8L, 138k Windstar. It has developed a noise that from inside the van sounds like it is coming from the right front tire area. It ONLY does this when traveling 45 to 65 mph, but not higher or lower. It sounds like a small dry bearing, where you can hear the high pitched sound of the steel balls banging into each other and rattlng around. BUT, every test I do says its not the rt frt bearings!?! Wheel play, left turning sound, rough sound, hand spin tire, drive tire off ground, high speed, all speeds. ABSOLUTELY NO indication that that bearing is bad!?! Putting it in neutral didn't change anthing. I put the engine in neutral , changed engine speed, revving, low to see if that had any influence, none. I also checked with hard slow turns too check cvs, which were fine. I checked just to be sure that the engine accesories were ok and they were. I also went over the pulleys and such at the front of the engine and found nothing. At first I thought idler pulley, but the bottom line is, this noise is definitey NOT engine speed related. Another member suggested tires. At this point, I really doubt it. Hub cap?

I'm really stumped. I geuss I'll have to spend more time with it under it on a jack or something. So, If anyone has some brilliant suggestions, I'm listening, what it could be, where to look, tests, etc.
Thanks

I had an`01 Windstar that made a similar noise and it turned out to be low power steering fluid.

Thanks, but I don't think so. Res. is full, I'd expect it to over flow with any more. Mine has the typical whiny Ford PS pump sound and some bearing noise, but nothing alarming. But the most important detail is that it is NOT engine speed related, but tire, vehicle, drive shaft speed related. 45 to 65 mph. I need to investigate the cvjs and bearings some more.
Thanks