I came across these pics and was wondering if i could install some 8" mid-bass drivers in the same location. SQ/imagining is what i'm concerned about. Would it fly or should they be installed/positioned somewhere else?

Mono Midbass?

Midbass is still directional. Subbass is not. You need to put your midbass drivers in a location that can properly hit your ears. That is not the place.

I know that these installs and ones similar to this have gotten popular in Europe and if you can manage the Haas effect, you've got a shot at decent imaging, but this isn't first on my list of approaches.

While it may be a spot to mount the drivers, the question I have would be why?