If you're an Apple Aperture user but wish you could use a different raw converter, BrushedPixel has something coming you might want to take a look at: Catapult. This Aperture plug-in acts as a go-between for Aperture and your raw converter and, through a workaround, even preserves side cars or Capture NX's edit information for future use. It's not a pretty system, as it involves Drop and Pickup folders and you'll have to set your converter to deal with those folders if you want to batch process images, but the idea looks workable.