they have curved headjoints. they are big. they are an octave below the flute. the diametre is 2-3 times as big as a regular flute i think, and they're pretty long. i played one once, and i had 2 reach far to reach the keys. bass flutes rock!
About 3 feet for the C foot. The B foot is 2 inches longer.
Not big at all. I'd say it's about 2 feet long and 2 inches thick.
Not really, but the key placements are slightly different due to the size of the instrument.
The largemouth can grow to twenty pounds or more.
It all depends on were you get it.