Besides the fact that it looks really stupid, the narrower you go, the less you can turn. If you think you'd like to do a U-turn with a 6" beam, forget it. The inside rear of the tire rubs on the inner fender.
Then there's the shock absorber issue. A beam you propose won't have a shock. The sellers tell you that a shock is unnecessary. This is complete BS. And illegal. If a cop discovered you had no front shocks, you'd be walking.