For more quicker, the Epson v700 & v750 are the way to go.
i can't comment on the software side of things (which will really speed things up with auto-detecting edges and whatnot), but the tray can take 4 lots of 6-long negatives, so 24 frames, in a single pass. Not as many for mounted slides, but probably 16 in one go (i've got the slide-mount frame somewhere I can check in the morning).

Or consider one of those places that will charge $0.50 per frame or whatever and multiply by number of frames and add in how long it would take you to scan yourself, it might be cheaper to pay someone...