"Joshua McGee"
Has anyone explored automated stock-card scanning using a photo scanner
with an auto-feed?

Joshua,
you may wish to compare machines from this Aussie link,
http://www.proscan.com.au/Scanner_comparisons.htm

It is PDF, and gives a wide range of choices.
If you see a scanner that may suit,
go to the bottom of the column, and click on the
scanner details link, which will give you
the guts on the model, the lamp life, what size of paper,
if it scans cards and plastic shrunk ID's etc.

It may give you some pointers about which to ask,
before heading to the shop.
(That's if the prices don't scare you off)