I've messed with this idea before, and it's basically related to the OpenCL particle stuff I posted a bit about last week or so.
I'm trying to do it in a low particle count, ultra fast way, using just point sprites. The reason I'm doing that, is because I want to be able to have enough horsepower left over to run a decent blur kernel on the point sprites. It's just additive blending going on here, so there doesn't even really have to be depth sorting, light, or anything fancy. This is the simplest physics calc going on - straight ahead gravity force. The "juiciness"/wavy motion, is coming from the fact that I'm shading the particles and influencing them with some noise and sin/cos waves.