Or just try
CIP1 or
CB Performance. But be sure to ask them for a 914 offset wheel. The VW wheels typically stick out too far, so if Flat 4 or their other suppliers don't have a 914 or 911 offset they should be able to tell you where else to look. And while you're talking with them ask the weight of the replicas. They're HEAVY compared to the real thing.
By the way, CB is an excellent place to go for carburetor parts, Weber or Dellorto. They were the official Dellorto distributor in the U.S. when those carbs were still being made and they're the ones who publish the Weber and Dellorto bibles that are so handy.