The Honig's K1 is very light but it is bulky. I just upgraded to it at the end of last year and it was bulkier than the other protector I had. My shirts fit tighter.
But honestly, who cares. The protector is there to keep you from getting hurt when the ball eventually hits you. Besides, the bigger you look the more intimidating you can be, the less crap your likely to take.
I wouldn't worry about how big you look. Worry about how protected you are. Most protectors are bulky, that's why they stopp baseballs from hurting you when they hit you at great speeds.