I had no idea Gene Berg was making 58 mm IDA down & side draft
carbs until I saw one at Mazdatrix today. They look just like a Weber.
http://www.geneberg.com/cat.php?name=The%20Berg%20IDA%20Carb&cPath=240

Now we would be in fat city if we can talk him into making a 58
mm side draft with manual mixture control.

Kind of expensive but no more than an EFI system.