I think it depends on what you are using to view the thumbnails. I don't know if they show up in Canon's software (I would assume they would) but if you're like almost everyone I know, you're not using Canon's software (and the same goes for us Nikon folks too). If you use PS/CS with Adobe Raw Converter and the updated ARC definitions (free on the Adobe website) you should see them in the file browser. When I first installed PS/CS, the ARC list did not include my camera, the Nikon D70. After I updated the list at the Adobe site, it worked fine. It may be that way for the 10D as well.
I use ThumbsPlus for my quick browsing and its an older version which does not have the current digital camera raw converters, so I also see only the JPGs in that program, even though they're in the same folder. I don't know know if the update to T+ will have the new converter, but it doesn't matter much because I use the JPGs for selection and editing anyway. I have kind of a convoluted workflow on this, and am working on a better one. After I import all the pairs of files into folder, I re-sort based on file type using PS/CS File Browser, then select and move all the JPGs to a sub-folder. Then I run a batch command to re-number all the files in each folder, so they still have the same numbers (with something more interesting than "DSC_1234") and the proper extension. I do it before I delete anything so I'm sure the re-numbered pairs still match up. Then I can go use the PS/CS file browser to flag whatever JPGs I want to delete, but I don't delete them yet. I move them back into the folder with the RAW files, re-sort by filename (so the pairs are next to each other) and delete both the RAW and the JPG of the same image, using the flagged files as my guide. I then copy the JPGs back into the sub-folder and auto-resize them as I do, to a size that's easier for viewing by clients. These are also the files I burn to a CD for copyright registration. I'm sure there is a faster way to do all this, but I'm still working on it. BTW, this is one of the reasons I bought a new faster computer. My last digital shoot had 876 RAW+JPG images, and my camera doesn't even make very big RAW files.
Andy Pearlman Studio