You could use GDK Particles, and texture them with a smoky texture, you would need to setup the emissions and velocity etc of them, but it would work...
You could also roll your own, like you said, using Plains... there is a tutorial somewhere in the dbpro forums about making a particle engine, i cant remember where though, a search should get you it.... i think it was written by a user called Phaelax from memory, but may be wrong.
Also, if you dont mind spending some money, you could purchase darkPhysics and use it's emitters, they are a litle better than the native GDK ones....
If it ain't broke.... DONT FIX IT !!!