Like the various inflammatory posts I've made about heatpipe cooler hype and payola to publishers of promotional PC palaver, I've posted many times about getting cases "for free" from computer shops with back-door recycling business, family members junking old computers, and the cyber-junk bins at county land-fills.
Somehow, I feel so much more comfortable taking a dremel, nibbler or hole-saw to a ten-year-old ATX discard case than I do about spending $200 on some kind of aluminum beauty and going after it like a butcher trims tenderloin. With the cyber-junk case, you may find some decent sheet-metal to work with, simple surfaces that don't complicate your work, and you can go at it with the abandon of Leatherface in Texas Chainsaw Massacre. Spending any amount of money on a case to cut up might make you feel like the victims in the same movie.
I wouldn't spend money on modding a cheap case. Just spend time on finding a free case to cut up. Under those circumstances, you could take two or three cases to construct a single case, using pieces and parts of all three.
Cases are getting better these days. More refined. Prettier. Still, some OEM cases from before the turn of the millennium were pretty darn solid. I saw an article at another enthusiast-geek forum where a guy flattened all the bends in a defunct OEM case, and then "re-folded" it into something different, like he was doing Origami swans.
Also, if you're going to do this, get chummy with two types of businesses: a sheet-metal dealer, and an electronics warehouse. I'm happier than a pig in s**t that my favorite choices of both categories are exactly, precisely right next door to each other.
