Unlike other RGBA modules for GTK, this one is written in C++ instead of C, and allows you to fine-tune your color map. Instead of just having two values - on or off - this allows you to control how transparent or opaque you want your desktop.
Instead of just "rgba = true" or "rgba = false", this module has the following syntax:
int rgba (int Red, int Green, int Blue, float Alpha);
Note: Red, Green, and Blue must be between -1 and 256 (not including the integers themselves), and Alpha must be between 0 and 1, with decimal places, and can also equal 0 or 1.
This may be more complicated, but is also more powerful. You will be able to actually configure RGBA to your liking, and tweak it to be as transparent or opaque as you like.
To build it:
g++ -fPIC -shared librgba-c++.cpp -o librgbacpp.so `pkg-config --cflags --libs gtk+-2.0` (Or just download librgbacpp.so from the Bazaar branch).
You also have to copy it into /usr/lib/
And off you go with customizability!