Hi,
I've just started using Pd, and my first project is to make some rhythmic patterns.
I'd like to start with a maracas type of sound, but don't want to start from scratch if I don't have to.

My thought on how to model this would start with:

• Generate N randomly delayed bursts of noise signal, sort of one for each bean.
  and then work from there adding filters and/or reverb to shape the sound.

Can anyone point me in the right direction?

I can not really, but I was just around..
Your ideas sounds good, I think.
Physical modeling would be best (as always..), but I guess it's a little too much since statistics will do a good job for large n as well. And statistics are closely related to noise..