Cappy:
There are several threads on this. PhilD and I have replaced the crappy H2 DRL's with 03 Lincoln Navigator foglight fixtures. They utilize a 9145 (45W) halogen bulb but can use a 9004 standard high beam bulb, or a blue xenon as Phil has used. It takes only minor modification to the air dam and replacing the bulb pigtail/wiring with a pigtail obtained from a salvage yard. Check out our threads on this and you will see/read all about it. There are also other threads using more expensive fixtures and more difficult installation procedures. Then you need either to jump the DRL's with the parking light relay or wire then to their own circuit/switch so that you can turn them on at night.
Ric
OMAHOG/IHOG
Hum2@cox.net