Sane doesn't support the hp scanjet 2400, but those ELCOT guys do have a driver for it (that interacts in some way with Sane, I think).
I understand Sane not including that driver in their backends for some licensing reason, but Mint is open to proprietary stuff. So it would be interesting to provide an easy installation for the hp scanjet 2400 by ELCOT, through the software manager.
ELCOT has a few other drivers for devices that may not be supported by Sane.
Not many people will find it useful, but it shouldn't be too hard to do.