I think almost ANY case I have seen is capable, as long as you have access to a 3mm or 1/8” drill bit.. amazon has brass standoffs with varying length threaded sections. Almost all cases have small holes for a 2.5mm standoff inside or little pegs to hold the Pi, so it should be easy to align the holes, plus using a 3mm gives you some “wiggle room” for the 2.5 standoff. Use the stand-off to mount the case to the holes on the monitor, then screw the PI in the case with screws into the standoffs. Or if the case doesn’t allow enough space for standoffs, use longer m2.5s to go through the pi, through the holes you drilled into the case, and into the mounts on the monitor. None of this should affect the lid going on the case afterward.

Edit: you also might be able to find a project box like thisthat is the right size (or close enough) to use the mounting holes on the monitor and cover both. Depth doesn’t matter, throw away the lid, cut the box down to the right height, and use the lid screw holes to mount the screen. These are ABS, so if you are feeling really adventurous, find one too big or a few that are too small, along with some abs sheet. Cut a box into four corners and then glue them together to be the right size. ABS is easily glued with some acetone mixed with some ABS dust (hit a box or sheet with a Drexel or grinder) brushed on the edges. It is also fairly soft and easy to sand away the joints.