I have a Kung greatbass, like what's described as a "contrabass" on this page,
item 3710:

http://members.aol.com/jblazar/KungRecorders/kung_recorders.htm

though mine has a single C key and is made of rosewood. I've tried a
subcontra (a fifth lower, seven feet high) in the same series and it
took a lungful of air on every note - continuous melodies were pretty
much out of the question. The greatbass isn't too bad, though for pub
sessions I prefer a Turkish G clarinet for the same job (louder, takes
less puff, more portable, covers the same range and then some).

Replying to catlin: you DON'T transpose for the treble recorder. You play
at pitch (or an octave up). For a folkie the point of that is that it lets
you play tunes with other people at the pitch they normally use - e.g.
try the fiddle strathspey "Miss Lyall". Most Scottish tunes have standard
keys, generally so they can fit the range of the pipes or first-position
fiddle, and if you transpose you'll be on your own.