I think if you would get a 400W MH with a spider light reflector (also called parabolic) and mount it perpinducular to the front of your tank it would probably give you the coverage you want. If you went with a 20K MH bulb you would probably not need actinic (VHO or PC) supplementation. Some of the vendors like Dr. Mac use 20K's over their coral prop. tanks without actinic supplementation.
I have a 58G tank wich also has the 3 foot width, I have a hamilton hood with a 250W MH 10K and two 55W PC's. I have kept about everything I wanted to keep in this tank. (i.e. clams, SPS, softies etc.) The only problem is that the light on the sides is a little less intense, but that is where I keep the lower light corals. My lights are mounted parrallel and without the spider reflector so I do not get as much light coverage. You could also use a 14K MH bulb which is a little less blue than the 20K. Here is a good supplier for lights: www.hellolights.com