1) A true Bi-Xenon bulb never changes intensity. The bulb is coupled to an electro-magnet/spring assembly, that draws the bulb inward when the hi beam function is selected. This effectively changes the angles of the light beam to appear brighter, causing a larger spread pattern.
2) As far as blinding oncoming drivers, if the lamps are adjusted correctly, you can have the upper "cutoff" aimed slightly lower than stock. This helps with that. But as we all know, many new cars have HID's/projector lamps that, even though they are stock, are significantly brighter than Halogen bulbs. Its the new generation so we had better become used to it.
3) I have done a considerable amount of searching for projector lamp housings for our truck and have not been successful yet. I do know of one member who fashioned his own set. It was quite involved, perhaps more than the average owner would like to get into. As you only have one shot to get it right. Then you need to buy a new set of housings.
You can say I'm an advocate of HID systems. It has allowed me to avoid several situations that very well could have been fatal to me and another person. I really do believe that on my Harley's, it is a necessity. This is all JMO. Take it as you will, I'm a big boy. Bob