I'm going to go out on a limb and say that it probably would in an 11" clutch bell. My reasoning is that the 11" bell is the largest and both bell and auto trans have to fit the same tunnel in the body. Now whether or not the converter needs to be supported at the rear I can't answer.

I wouldn't attempt to use a torque converter unless you also use a functional transmission attached. You can use the converter front cover and ring gear with the guts removed with a bellhousing , auto trans case,or a fabricated starter mount if you like .

Correct, if you use a convertor that has the guts in it, the internals will wobble around and cause an out of balance condition. I've used a 130 tooth flywheel with my 727 bell and it works just fine so I don't see why a convertor wouldn't work with a manual bell. This 340 is running in this pic, 130 tooth flywheel with a cut off 727 bell. A 143 tooth flywheel won't fit in a 727 bell.

Pretty cool idea.

I made mine after a trip to the metal recycler...
I use a bellhousing and fluwheel, and the rear mount can be swapped with a wood block to run an automatic complete including running through the gears.

I made a bracket that bolts to the block using a bellhousing locating pin for reference; tested it on one of my motors on a run-stand and it worked fine. I used to sell them and valve-cover spacers when I had my tool biz. Wasn't enough of a market for that stuff for me to break even.
All it takes is a small flat bracket; mine were jet-cut 3/8" aluminum.