The other auto option, one that would be excellent except I'm not willing to go down that path AGAIN, is fit a 4HP24EH from a P38a, and use a compushift to control the shifting/ lockup etc.
I still have the ZF adapter kit etc incase I get a rush of blood and decide to actually try it, as I think that the huge TC that the P38 utilises would last behind the 4BD1.

JC