Tominizer - I have the exact same issue. Mine started after I had my CV boot replaced, and they thought it was the axle. It wasn't. I have posted stuff and tried narrowing it down to a couple answers. I have had no luck. The only thing that I think is different is I don't think my ticking noise gets faster with speed. Mine only shows up from the 20 to 40 mph range.
I really hope you (we) can narrow this down or actually come to a clear answer. If you need all of my info on this topic I can relay this to you via PM. FYI - I have an 02 4.6is with 90,000 miles.

Good luck and thanks.

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Eazy wit da Haaahdwaire!!!!