There is resolution, and then there is theoretical optical resolution and optical resolution. An Epson 750 claims 6400 dpi. This is, of course, ridiculous, as we all know.
Resolution is simply a count of how many pixels a scanner can generate. It's meaningless (mostly). Theoretical optical resolution is the resolution the scanner should be able to do based on the engineering specs. Imacon was famous for quoting theoretical numbers, especially for its DMax, which exceeded that of film (theoretically, but not in real life.) Optical resolution is based on how many line pairs the device can separate from a real piece of film. I have never tested either of these devices personally, but I doubt either of them would achieve anywhere near the optical resolution, which is the number that actually makes the difference….
We are talking about CCD scanners here and none of them can exceed somewhere in the range of 2000-2400 ppi. The Eversmart Supreme gets bit higher by using a lawnmower pattern for scanning, but its clear the technology of the CCD chips being used is maxed out at that lower level. By comparison, drum scanners (using PMT - Photomultiplier Tubes) go from 4,000 to almost 8,000, depending on the device.
Lenny