using the cockloft for loft space?

Hi, As part of a renovation to the top floor of our 3-story framehouse, we are exploring the idea of jettisoning our cockloft in order to raise our ceilings to 12′ and build in loft space in our kids’ rooms. Has anyone done this before; can you speak to pros, cons, costs, and anything else you think might be germaine? Our ceilings are currently 9′ and the cockloft seems to be about 3′, giving us roughly 12′ to play with (minus whatever insulation or finish we might need to add to the currently bare underbelly of our roof. We are thinking mainly of putting in a loft for beds, not necessarily something they could stand on (we only have 12′ total vertical space to divide) and using the underneath for various uses – possibly desk, closet storage, or even laundry. Anything that could be at ~6-7′ without suffering . . . Thanks for your thoughts forum!