But who knows when it was actually release as a box.
The 5speed came out in about 97, maybe a year before, so I wouldn't be surprised if they had 6speeds not long after.
But as for the question, the bellhousing is removable (well it is on the 4spd's and 5spd's.
You just have to find out if it is the same pattern as the 4speed and 5speed boxes.
Then you have to find a 4cyl late model rwd Toyota that can with a 4cylinder and automatic tranny.