Not going to happen (unless you consider
Glass Lantern). Resco might, but I doubt it as it's tough to keep up with the proprietary RAW formats.
Your best bet is one of these options:
- Set the 20D to take RAW + JPG (the 20D has several levels of JPG from which to choose and it can capture both at the same time)
- Set up a batch process (in PhotoShop, for example) to process the RAW and create JPGs
FWIW, I no longer capture JPG, only RAW, unless I have a very specific reason to create the JPG in-camera.