@Radlafx...Interesting...I'll have to give this a bit more thought then.....

I know the RAW files out of my D70 are all different sizes...I attributed that to the fact that those RAW files ARE compressed in cam.
My understanding was that the RAW files out of the 20 & 30D were UN-compressed...but, perhaps there is some proprietary "processing" going on with the Canon RAW files as well.

There is additional info stored with each image other than sensor data that makes up the image file itself...various tags and exif data...but it shouldn't be that much different.

Try a little test...take both your 6 and 11 Meg RAW files and convert them to 16bit TIFF's...do they come out to "roughly" the same size?

In youth, we learn....with age, we understand.