Am I the only one who's noticed that the NPR auto transmission is an Aisin A450? I've seen pictures of them on eBay. The A440 and A450 both have a detachable bellhousing. Am I the only one who's wondered if the front side of the A440 and A450 might happen to have the same bolt pattern? If so, you *might* be able to use an NPR auto bellhousing on the front of an A440. Of course, you'd still have to deal with flex plate and torque converter issues, but it's a possibility...you'd probably have to have an A450 and an A440 next to each other to figure it out.
Steve
P.S. Google never ceases to amaze me. This quote: "AW450-43LE is a replacement for the JR403E
truck transmission and is similar to Toyota A442F." comes from this .pdf, which seems to indicate a lot of parts shared between the A450 and A440/442:
http://www.shinseiauto.com/japanese/.../ata440f04.pdf
Also, according to George (orangefj45) it may have only been used in NPR's from '98 up, so you might not have one in your back yard...