Hello, this is my first post here. So I hope that this is the correct place
After experimenting for a while, I have developed a technique to simulate volumetric clouds using particles, subsurface scattering and composite nodes. This technique does not try to be a substitute of real volumetrics, however, it can obtain quite real results.
I include an attachment with the result of the applied technique and a link to a document describing in detail how to implement it.
I hope that this can be useful for you guys.
I just uploaded a pair of test images. Rendering time:
cloud-01: 02:17.89 mins
cloud-02: 01:48.29 mins