As I've mentioned, CS4 Camera RAW 5.2 gives you some additional Camera "Profiles" in the Calibration tab. Still in beta, Adobe has the DNG Profles Editor which lets you take a DNG file, presumably converted from a native RAW file format, and make very specific adjustments to how it is rendered. You can then import that "recipe" right into the Camera RAW "Camera Profiles" menu.

Here is the Adobe Labs site, with some good instructions and links to the Editor.