why cant I get a low beam headlight bulb for my 1998 Lincoln Mark VIII

those headlights are not produced anymore and we have not been able to find a replacement anywhere, so the real question should be: How do I replace those lights with ones I can buy?

They are HID ( high Intensity Discharge ) lights , special on this car. Found replacement on ebay ($ 88.00 ) for used bulbs , got Halogen bulbs @ auto parts store , they fit the HID bulb openings , have to rewire and omit the ballasts, take the ballast feed wire and connect directly to new bulb plug.