If you want something custom or diffrent, build it. It is a sure way to get it like you want it. If you want a basic old flatbed buy one, they sell for cheaoper than you can make one for. Price them out and ask what they weigh. Steel is selling to the general public right now for about $. 80 per pound (twice what it was a year ago at this time). Figure a dollar because you will have waste. That means a 700 lb bed plus lights, wire, paint, etc, etc..... you'll have a grand in it plus time. New units start about $1100. My $. 02 worth, tax free.
-Scott