I am the developer who did the Fuze+ and X-Fi 2/3 ports. The Creative ZEN uses a SoC very similar to the imx233 which can be found in the Fuze+, ZEN X-Fi2/3. Also if I'm correct, the Creative ZEN is very very similar to the ZEN X-Fi (read: basically the same). I have begun some work on the ZEN X-Fi. I think the amount of work to port to the ZEN is very moderate once the ZEN X-Fi is done, it could amount to only change a few settings/pins here and there. Both ports could even be done at the same time.
Depending on how much you want to get involved, you can try to run code on the device and play with it or even do some reverse engineering. I advise that you come on IRC in any case, I can give you many tools to avoid starting from scratch.