Trying to make a 2D smoke element have 3D volume.

Hi there, 

I have a 2D smoke element (it's a smoke cloud MOV with alpha) that I would like to have panes of glass intersecting vertically and horizontally.  Normally I would just create the smoke/cloud with something like Nebulosity to have a real volumetric cloud, but the client has a specific smoke clip they want.

Is there a trick to adding voume to a 2D layer?  I thought about layering it each with 20% transparency and off-set just a bit in Z space. Then the glass panes would be more visible in front and slowly fade further back.  But, then I'm getting sharp edges when the pane intersects the smoke layers.  If I could round the layer or bend it that could work, but wonder if there are better ideas out there.

Any thoughts?

Thanks!
-Stephen