What brass instrument should I learn?

So I've been playing flute for 5 years, and I've recently taken up an interest in joining a drum corps. Unfortunately, flutes aren't exactly allowed in drum corps. So I was thinking about learning to play a brass instrument in case all my hopes and dreams come true! But I was wondering what my best fit might be. Obviously you people don't know everything about me, but what do you think an experienced flute player would excel at? I know that embouchure wise, tuba is the closest match, but I'm not sure I'm built to lug a 40 lbs instrument around a football field. :P