I often use this type of visualization when I want to show something in a flashy way.
I have the exagerated slopes going to a layer with a 25 percent transparency. I have my design contours greyed but solid and you can see the differing slopes by shaded greys.
I could have the entire landfill shown with the existing surface on in a greenish representation for slopes and contours allowing me to represent the design with existing in 2d but with a bit or visual relief hocus pocus.
C3d can do wonderful things.
How much horsepower do you have and how much time.
this is with 16gb ram and a 2gb graphics card running on a laptop with 64bit CAD and 3ghz quad processing (guessing at the 3 ghz) I can pan almost real time.
Looks good - we do something similar. I find bas relief imagery to be great for LiDAR representations of topography as opposed to contours and elevations. Believe it or not, we present to some people who find contours difficult to read or interpret.
I've got a desktop i7-3770 @ 3.4GHz, 8 cores, .16Gb RAM, Win7 64bit. GFX is a 2Gb ASUS HD7770. A decent system but Civil 3D still drags as it's not multicore capable.