etaf,
there are a couple ways of looking at this situation - MONEY versus TIME -
1. if you buy a DEDICATED 35 mm scanner, MOST of those have an auto-feed that you can then load the magazine up, go do something else while it does it's thing and just come back occasionally to reload the magazine
2. with the flat-bed units which are CONSIDERABLY less $$$$, by a long shot!!!, then you are going to be spending a whole lot of TIME sitting there reloading the scanner

'cause there really isn't time enough to leave to do anything else - you have to sit there to click the buttons, or it just waits for you
we first made choice #2, an epson 4490, actually was VERY pleased with the results, contrary to what i have read on-line of some people expressing dis-satisfaction with their choices, though i never read any that were using the epson scanners
do be careful of your purchase in this respect as the manufactures changed the technology used in manufacturing, right after we aquired our unit - so maybe that is also what many people had their problems with, so....
3. you can also buy / build an adapter for a digital camera - this is probably the BEST choice of all, ESPECIALLY if you already have a good quality dslr camera - again though, TIME is a factor here, i never really 'engineered' an auto feed mechanism for the one i made PJ to use with her fuji - that was economically feasable - i could dream up plenty of BIG ideas, but $$$....
you might also consider what we also ended up with - did buy a nikon dedicated scanner - aquired it 'used' from craigslist - was almost a new unit, we only paid a fraction of it's new cost - previous owner had a large number of slides to scan - bought the scanner, did their thing - then sold it to recoup some of the cost when they were finished....
really can't recommend any of the dedicated units in particular, will say we have been VERY happy with the results of the nikon super coolscan 8000 ed we aquired
depending what she wants to accomplish is the choice she makes upon the time frame involved - for the ability to make LARGE reproductions - the nikon is good - so is the adapter i made her
hope some of that helped you to make a choice....
good site for some reviews here:
http://www.imaging-resource.com/SCAN1.HTM