I contacted EPK separately a few months ago, unaware of the group buy, and inquired about compact size CZ barrels. They replied there was no plans at this time.
The original group buy never had enough interest to actually happen. As far as I know there is no source for a PO1 threaded barrel at this time. You could however send your barrel out to have it threaded or a local reputable gun smith or machinist would be able to do it for you and shouldn't cost too much.
Interesting.
So, for the compact guns, would we need to get a full size/length barrel and then get it cut down, recrowned, and threaded? What length would we need?