That is what the lampholders look like on my halfpiper. If anyone has the same exact lampholder, just PM me and we'll see if I could acquire it. I'll try hard to convince my parents ;)
Hey Vince, I wonder if you fixture is compatible with the Leviton bolt on style lampholders like the one in my gallery. The starter end could be a problem but it looks like that the starter base should bolt on the Levitons. Anyways Home Hardware might sell the Leviton bolt on holders.