Even light distribution with a single bulb.

I have been having a hard time getting any solid information about what reflectors offer the best wide angle light distribution over a square shaped growing bed.

I read that P.L. lighting offers perhaps the best computer designed reflectors, though they all seem pretty narrow angle (60 degrees or so) and are intended for mounting a couple-several yards above the growing aria.

Does anyone know or have any solid ideas where to look for a reflector that would suit a single low mounting light over a square growing bed?

I have been looking at 4' cones and umbrellas (parabolic, both vertical and horizontal bulb mounting). also the adjustable wing style and the addition of light spreaders in versicle mount reflectors.
Am also completely open-minded to enclosed reflectors as well. (as long as they do the job better than the alternatives)

I'm realy just looking for someone to say "X works best with a 250w over a 3x3 foot square bed" or "Y works best with a 400w over a 4x4 foot square bed" or "Z is best for a 600w over a 6x6 foot square bed" and "W works best for a 1000w over a 8x8 foot square bed"

I realize the examples listed is the extreme limit of what could be hoped for allowing only 2000-2500 lumis per square foot in ideal situations, which is why the most ideal reflector (or reflector/spreader combination) is being sought.

A know 1 person who has used a light diffuser and said that he had improved performance with it; I have never tried them myself. I use a nearly square a/c reflector with my 1000w HPS over a 5'x5' area with no light diffuser. It's true the light has a hotter spot below the bulb but I just create a bowl or crater shape with my plant canopy to minimize the hot spot effect. My plants are always happy with dense solid flowers and generally even development across the entire growing area. Bulb light is a point source and the reflector will never be good enough to make it a plane source, so save yourself some headaches and/or $ and work within the limitations of the most common(and cheap) reflectors. You CAN achieve excellent results with a cheap moisture/light meter(Home Depot around $7), a mediocre refletor, and some patience....trust me, I do it monthly.

I have been hearing mixed things about the light defusers (spreaders) it seems its more the manufacturers that have good things to say than the users or even retailers in some cases..
A distributor I spoke with whom seemed quite knowledgeable/experienced suggested the silver sun parabolic reflector. I would still like to hear from any others that might have suggestions or experiences..

Does anyone have experience with the Silver Sun or Sun Soaker (HTG's knockoff of the Silver Sun) reflectors?

I looked up some reflector info and the Sun System Blockbuster seems to be a good choice for a square growing bed, maybe that would work for you. The reflective insert looks to be of high quality with an adjustable lamp socket and the price looked good too. I am guessing that this paired with a light meter will allow you to achieve even lighting across a growing bed.
I also looked at the Silver Sun and I like it except for this: Although the parabolic shape with the v-strike bend does direct the majority of light rays downward, they do not all travel the same distance and therefore are not all of the same intensity when they reach the plants. This seems like it might cause as many problems as it fixes; just something to be aware of. Good luck, I hope you can make the best purchase for your garden without breaking the bank.