I have a set of the Chicago Cycle Specialties trees. They are at my other house in Georgia, I'll be there the end of the year and will try to get a picture. I think they are 3" narrower, they look a lot like your set.
The most prevalent aftermarket supplier of stock style FL aftermarket trees that I seem to come across the most is ZEL's. Heres some info from Masterblaster, who ever that is.
ZEL stands for Zodiac Enterprises Limited.
Its the Asian Branch of the Dutch Wholesale Company Zodiac. They distibute their parts worldwide and manufacture products for all the other big names in the industrie. They are ISO 9001 certified. Ton Pels, former European Dragracer is president of Zodiac.They were a big supplier for Custom Chrome. They are out of Hong Kong. They also made headlight buckets, Master cylinders, among others.