Delta Six Indistries is now Euro-American RV Products. I don't know if they
were bought or just changed names. They distribute Westfalia camper parts
such as the skylight, water filler and electrical hookups, potable water
pump, etc. I just ordered a couple of parts and got good service and
better-than-dealer pricing (these are still expensive parts!). Here's the
relevant info:

Euro-American RV Products
5517 Cleon Avenue
No. Hollywood, CA  91601
ph  818-760-4214
FAX 818-760-4216