I'm interested in how the shield throws HID light. I don't think modifying the bulb will help with the blinding because it will be how the reflectors project the light that controls the beam pattern and not the actual bulb itself.
The reason its blinding to have HIDs in halogen housings is because the way the reflector housing is positioned reflects extremely bright even if your main beams are lowered down like spanky said.
So... for example, even if your beams aren't directly pointed in somebody's eyes, if they use their own energy to look directly at/into the housing's reflection itself although they're outside of the main beam pattern, it is still very BRIGHT just because the HID optics are being reflected off the whole inner housing and not controlled through a true projector.
That said, I have HIDs in my 05 halogen reflector housings and have them aimed so its not terrible to oncoming traffic and haven't been flashed once since readjusting the beam so really anything is possible. Like litebrite says don't let nasioc get you down, to each his own, but just remember if it doesn't work out you'll be pissing off all the oncomers! I'm very interested in seeing what a shield could possibly accomplish in reflector housings. Hope my info helps and sorry for the rant... subscribed.