Hey tr63, good man for jumping into the new sub section!
I am not fully versed on all makers and their variations. There is a good description by a member that I will have to go back and see if it can be linked. In the meantime, Badger is looking to be able to migrate all those discussion over the the "Semi" section. Tall order as sometimes the two morph together in one thread.
The MAIN four builders that I am aware of, and most now DO NOT build semi auto Brens any more, are Historic Arms (unclear of status), Project Guns (retired), WiseLite (no longer building Brens), and SMG Guns (no longer building Brens). I am unclear it Midwest Metals Creations ever did Bren guns. He apparently sold semi auto parts for the Bren build at one time. So many of the builders/suppliers from years past no longer do so. The supplies are dwindling, unless new stocks are found and imported. Sadly, as of today, no more barrels will come in without being cut up. And it seems the only builders now are individuals doing it for themselves.
IF you get the opportunity to purchase a Mighty Lime Bren, I think that would be a VERY good investment. They are exceedingly well built and have some solid engineering behind them. He does not build for sale, but he had been listing a couple of his guns on GB in the recent past.
There is Kiwi Custom Guns. He appears to be building still? Try this link. RESTORATION | kiwiscustomguns
It was Joe H under the discussion "Wise Lite Arms semi auto only Bren".