You can do something similar to this already.
If you have the Compact screen enabled (you need to have installed GD for this) then you can look at the interfaces on the Compact screen, and sort them by incoming, outgoing, current max, or 95th percentile. If you sort them descending, then you will be able to see the top 10 this way.
It is not really feasible to calculate the top 10 over multiple files, since this would require a bit too much work by the CGI every time.
Steve