there's a german ( or austrian?) company selling a one pot brewery with automation that uses something like a big colander.
The difference is there's no side holes.
Side holes will cause more fluid to take the short path of least resistance out the side of the colander thus reducing the exposure of the starches to the enzymes. How dramatic this is, is anyone's guess. It might be meaningless, it might be substantial. If you use a grain bed agitator like a little propeller on a motor, I bet the colander holes would be moot.
If you decide to try it and find that you get channeling off to the side and weak or very slow starch conversion, you can take a little zip saw to the colander slice the bottom off leaving a little lip of about half an inch and use that as a false bottom. I'd cover it with SST wire cloth.
In theory the larger the surface area of your false bottom the less likely you are to have a stuck sparge. Of course one can overwhelm any amount of surface area with lots of gluey starches like those from oats.