Clever idea. That's part of the fun with these things, being able to "think outside (inside too) the box".
So, is your conclusion that a box without sound holes produces better bass balance? My main instrument makes a really quiet, trebly sound played acoustically, so I usually plug it in. If blocking off the holes would improve the bass, it's an easy decision whether to do it.
Calculating the volume of the body and area of the soundhole(s) could allow you to tune the body to emphasize the bass frequencies. Maybe I'll have a go at my No. 1 and see what the resonant frequency calculates to. Maybe I can just tweak the soundholes and get more bass....