Here's an idea. What if someone create a short fan duct designed to feed the graphics card/radiator with fresh cool air? similar to engine intake designs they have on cars.
Because if I'm not misunderstanding a lot of the issue with current ultra small cases are mainly cooling efficiency right? For example small cases like the a4 and zaber sentry (and c4 looking at these preliminary testing) can benefit a lot if cool air can be properly directed to where it counts and have more air pressure built up inside the case by leaving 1 or 2 air ways for exhaust instead of just have ventilation holes everywhere.
For the ducting, we can have one end attached to the case panel and the other attached to the edge of the fan shroud on the gpu. The end on the panel can be secured by screws but the other end (graphics card side) can be secured with clips that we see everywhere on smartphone mounts. Just clip the ducting bracket onto the outer edges of the gpu fan shroud.
Make the tubing flexible so it can accommodate varying angle and distance from one end to another because some gpus are thicker while others are thinner.