A 6x9 scanned at 4000 dpi (Coolscan 9000) is on the order of 120 MB.
I don't want to be argumentative here, but:
1. A 21MP Canon 5DMkII file is a compressed file on the data card. It's 24MB on my hard drive. But, when opened is actually a 60.2 mB file.
2. When you scan a 6x9 at 4000 dpi, might you be 'overscanning?' Just because you get a large file, isn't there the possibility that the additional resolution doesn't include any more detail/information than would a 2400dpi scan?
3. Digital file sizes don't really equate to analog scan file sizes.
4. Digital has a higher acutance, so that even if a film scan has slightly more detail when examined at 100% on screen, in print, the digital image will probably appear to be sharper. Stuff captured in minute detail on film may not resolve on the paper.
5. When it's all said and done, i still prefer the look of film. I'm getting closer to being able to get a digital file to look like film, but unless i forget the source, i sometimes feel like i 'cheated.'