Hi.
Big-in have a handful of Turkana PBB still. (including my old girl)
They are the only place you will find them, and sadly they refuse to have them leave Japan.
Missing a trick really as they could make a lot of money exporting them.
Also getting fish out of Japan can be a pain, but is possible.
I came close to setting something up for some contacts in SG once but when I saw the things both parties need to do, it really was too much hassle.
IMO, there really isn't much difference between Turkana and PBB.
I noticed the difference in mass, and also coloration.
The Turkana head is slightly different too.
As for Kamihata, they no longer produce F1. They stopped that a long time ago, and the quality of their Bichirs now are pretty low IMO.
Do yourself a favour and enjoy your Chad PBB.
As for getting Turkana PBB out of Africa, King-eL pretty much summed it up perfectly.
Most of the fish supposedly are in the deeper part of the Lake which I think is in Ethiopian territory, and is controlled by some very nasty people.