I can not promise that it will, but it sounds good and I'd certainly like to try it. I am currently evaluating some other software renderers too, and still have to decide which one to use. But if you'd do me that favor with the zBuffer fleld, I will keep you informed of my progress in hacking the Framebuffer and any possible results.
Do you know whether it is possible to access the z-Buffer in the jCPT engine? I know that it will probably not be possible when using hardware support as graphic cards usually do not (and physically can not) export it. How about software rendering? I'd like to use it for post-rendering graphical effects.