The only way to do this would be to find a K50 from a AE85 that was only available in japan... the K tranny doesn't have a removable bellhousing and K engine bolt pattern is different from A engine.
On a good side, a T50 tranny from a TE2x, TE3x TE5x, etc will accept your stock driveshaft, same output spline count, same dia and same tranny length... and it will bolt behind a 4A bellhousing with minor modification (but you need a 4A-C manual bellhousing to pull that one off...
Or you could get a whole 4A with it's T50 tranny but you'd have to cut the transtunnel a little to accomodate the shifter that sits a couple of inch backwards and you'd have to swap the driveshaft yoke for an AE86 22 spline yoke... but overall length is the same.
Hope that helps you.
1977 Toyota Corolla TE31 (traded)
1974 Toyota Corolla KE20 (Project)