Oh wow thats pretty cool John.

Well I unfortunately couldn't find the site
but I did find the scientific name of the tanzanian subspecies.
There are at least 2 subspecies of Adspersus
There's the south african bullfrog
Pyxicephalus adspersus adspersus.
Which are the kind most common in the pet trade and they also get the largest.
Then there's the Tanzanian bullfrog
pyxicephalus adspersus angusticeps.
From what I've read they don't get much larger than edulis, males max out at about 5 inches.
Maybe you can found some info with that.
I will still try to find that site though.