Is the 4l80e torque converter cover the same as the Th400? Does the Th400 even have a removable cover?

Anybody know where I might find one for the 80e?

It should be the same. Don't hold me to it, but it should be and the 400 does have a removable dust cover.
Best bet to find one would be a salvage yard or your local pick your parts yard.
Worst case, you might have to go to a GM dealership and order one through them.

Edit: Some digging around I found something that said that the 4l80 has 6 bolts holding the dust cover on and the TH400 only 4 bolts.

Some of the older heavy duty "K" 400 cases came with 6 bolt dust covers as well. I am not sure if the 2 are compatable but I would think so.

Ive got a cover for the 80