To make up the difference in lumens between a 400w light and a 1k light (a difference of about 90,000 lumens), you'd need to use 45 30-watt CFLs. That many CFLs would eat up 1350 watts of energy, and generate way more heat than a 1k light.

CFLs have their place, but trying to emulate the lighting power of a 1k light is not it - they can't do that efficiently. If you need or want that much light, get two 600w lights (180,000 lumens), or one 1k light (145,000 lumens). There really is no efficient substitute for those lights if you need that much lighting. That's not to say that adding some CFLs won't help; they will. But don't get too whacked out on them trying to make them do what the bigger lights can do, because CFLs can't do that cost-effectively.