Proximity problem solved.......
I just replaced yesterday one black iphone 4 broken glass. Proximity sensor didn't work. I was going to replace glass again. Before I replace the glass I decided to do a simple restore (4.3.3).
It worked ...............
Soooo it's not a hardware problem. It is software problem.
I guess : When you restore your iphone with a new firmware it measures your glass darkness and backgroud reflections while you restoring the new firmware. It also measures all hardware components. I am sure data kept in some files. When you replace the glass, new glass darkness and reflections are usually different from previous one (sometimes). You think your glass is bad. But your new glass works on other iphones. That explains everything.
If your proximity is not working --> You can simply restore your iphone to 4.3.3 (I just tested once and it worked with custom firmware 4.3.3 created by sn0wbreeze)
I hope it works for everbody.................
I have been working on this weird thing more than 2 months.