Hey David...and Brian!
HERE is a thread on the slimming down of DVD cases...but it also is frequented by posters who have moved their collections into binders.
It is a 33+ page thread...but if you want to skip to the end...take a look at page 25-on. I think you'll get a good idea what people have been up to.
I'm an advocate of using slim cases or ThinPaks to downsize my collection. They take up about half the shelf space of regular size Amaray cases. But there is the expense of $$ (to buy the new cases) and time (to either cut the old coverart to fit the smaller case or scan, manipulate/shrink and print new cover art). There are many different ideas kicked about...so I think you'll get some ideas there.
Good luck!