I may be mistaken but I don't, think that is quite right. There were certain versions of 904/999 that were specifically for the v8 engine. The op has already researched and identified certain heavy duty versions that have been made with wider bands etc. I noted small slight differences on the heavy duty v8 versions such as a thicker output shaft support, larger diameter servos.
The trans that he wants with the low gear, heavy duty v8 internals and non lockup, never really existed outside of a police car as he noted. It has to be made or converted if you will.
I called A&A trans about a tranny like this and they too identified to me that this type trans requires some pump modifications to be made.
To say it is easily or cheaply done is all relative. But it is not to my knowledge just a matter of swapping parts. But this trans can be built. I have done it my self personally including the machining of the pump.
