I seem to recall seeing these in the "handbook of the Japanese Army" - a series of books in the 80s(?) which were based on intelligence pamphlets the USA produced in WW2. They had multitudes of battalion types, brigade types, etc (Bns with 4 coys, 3 coys, coys with 3 and 4 platoons, an assortment of support assets (some bns with 4 70mm guns, some only 2)).
In other words, just as horrible a mish-mash selection of "official" TO&Es as the Jerries had, just in a smaller army.
And then the Japanese Navy had its own army as well. And land air and bombers, tanks etc. and the army ran their own supply convoys separately from the navy ones. Japanese inter-service rivalry was intense, to put it mildly.
This site came up on a google, and seems to have the same sort of info as the previously mentioned guidebook:
http://www.1jma.dk/articles/1jmaIJAc2.htm
No idea if it matches what we have - but we did have input from a Japanese history buff in the early days, who had his own website (Takai?). Plus a couple of the OOB team we had in the early days were into the Japan-China stuff.