Well, I contacted Cooper Lighting and they said to "contact my local Streetworks reprisenative, Shamrock Power." Cooper manufactures the fixtures, you would think THEY know the answer, right? They just don't like answering simple questions....
UPDATE: this is an email i got:
"Michael,
Sorry, I was able to confirm today that Cooper Lighting no longer manufacturers the URB fixture and has no replacement.
Shamrock Power Sales"