Hydroboost has been around for years and years, for most medium and light duty trucks. GMC/ Chevy use a hydroboost for the 2500 series and up trucks. Nice units, interestly, they share fluid with the steering systems.
Also, you can make valve cover spacers to add height to the standard valve covers. The spacers are painted the block color, and have the stock chrome valve cover over top to have a stealth look. I know someone who did this, and it looked like a good Idea, and not obvious unless you know it's there.
