I have just completed re-doing the interior of a commercial bay I own and use for a hobby shop/man cave. It is 20 x 30 with a 12 foot ceiling. I installed 36 4 inch steel boxes with a cheap porcelain incandescent bulb fixture and an 18 inch diameter shade I made out of 1/8th inch PVC sheet. The fixtures are arranged in four rows of nine on three circuits. The spacing is such that there is a bulb approximately 5 feet in all directions. I use 100 watt equivalent, 23 watt actual, 5000k color rating CFL bulbs. There is very little shadow and while I have not actually measured the lighting level it is very bright. The total wattage for the shop is less that one KW. There are no ballast to burn out and there is no flicker. If I break a bulb or one burns out I only need replace a two dollar bulb. The only down side is they take about a minute to get completely bright.
I did this somewhat crudely in my garage at home when I got tired of replacing tube type fixtures, the results were so good that it was clear to me what to do in my new shop. Everyone comments on the lighting when they visit my shop.