Does anybody...

I use Rhythm Rascal but the freeware limits you to .wav only unfortunately. It does let you save and if you have a prog that can convert files then you'd be set.

Rhythm Rascal itself is dead easy to use and really lets you arrange the beats you make into a song very easily.

Hope it helps :p
Cease
 
I use Hydrogen with the colombo acoustic drum kit to slap up some drums, export them to wav, and then import the wav into an audacity project for recording/mixing.

It might not be the best sound on earth, but for something quick and free, I like it.
Here's an example: http://vinterkrig.org/opptak/testing/fallenstar_slagverk.wav
Something quick made for doing a norther cover once.