would a smaller sound hole in the back of an accoustic in addition to the normal sound hole on the top completely destroy any and all sound from it, or would it be alright?

Regular accoustic, not electric accoustic.
I wouldnt try it. It would most likely come out sounding all disoriented and awkward. If you really wanted to try it though, I would test it out on an old acoustic or a cheapy or somethin.
'member The Pit of 10'? oH, I 'member!

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It would wreck the integrity of the back, which vibrates just as much as the front/top does. Think of an acoustic guitar as a speaker. The body is designed to amplify and transmit the soundwaves out of the soundhole. What happens to a speaker cone if it get's a hole in it?
Try this with any acoustic. Strum a few chords with the back of the guitar held up close to your body, nice and snug. Now hold the guitar away from yourself so that nothing is touching the back or front, and strum the same chords. Notice how much louder it is the second time? This proves that the back is resonating along with the top to produce the sound.
^^I like that analogy.

RSX, if this was a good idea, don't you think guitar manufacturers would have done it already? Many manufacturers and builders have already experimented with sticking holes in weird places. Ovations have a cluster of holes off-center on the upper bout, I've seen some custom builds with a hole in the upper side, and really these are the only alternatives that make any sense.

Putting a hole in the bottom side would direct the sound toward the floor, putting a hole anywhere in the lower bout would destroy the volume and bass response, and putting a hole in the back would make it impossible to play without muffling the sound with your body.
I agree that this is a bad idea, but just out of curiosity, what would you hope to accomplish by doing this?