Hi Brad,
Never done a time-and-motion study of this particular set of operations - but you what? Not a bad idea to haul out the stop-watch and do it. But first I need a spec from you - what resolution, linear dimensions (output from 35mm negs) and bit-depth would you like to see for such a test? The specs, for example, could be say a 9*6 linear photo at 360PPI (ideal for Epson printers) and 16-bit depth. This combination of settings would generate a 40MB file. But if done at 8-bit, it would be about a 20MB file. Of course if the colour working space will be ProPhoto, one should automatically scan at 16-bit depth. So let me know what specs I should test and I'll revert.