Old hat man! Ten years ago you'd have been crazy. Now you can do it fairly easily. Just be efficient. Of course with lanky leggy sativas it'll never happen, but with high yield strains, I'd say you ow it to yourself to get a gram per watt. Also, two 400W should get as much or more than a 1000 because they can be hung closer and you get 2 points of light instead of one.
448 g from a 400W light should be easy with a SOG or SCROG type grow, good clean water source, a well reviewed nutrient feeding program, and a well planned closet. Reach for the stars, these yields just keep getting higher and higher every year!