I contacted Fleetwood concerning replacements light assemblies for my 2002 Pace Arrow 36R. Was informed that the assemblies are no longer available but did direct me to Sterling, the manufacturer. I called them and it turns out the headlights were OEM products for a BMW 7 series. Hella still provides bulbs for those. You may be in a similar situation.
Perhaps not exactly the answer you were looking for, but it may help.
Wayne & Christine: 2002 Pace Arrow 36R
Molly, Maggie, & Mookie (Tres Amigos)