I wish you luck on this.
Indeed, many "not in demand" (translation: "not cheap") Cd/DVD cases have gone off the market in recent years. Some of my favorites are gone too. I've had to redesign packaging more than once because of it.
Generally all you find in the "smoke" style these days are in colors. For example:
http://www.mediamegamall.com/khyperm...5-p-15897.html or
http://www.mediamegamall.com/verbati...78-p-5633.html or
http://www.mediamegamall.com/imation...85-p-5169.html
Translucent blue or purple is about as close as you can get.
Even eBay doesn't seem to have things like it used to. (At one point, there were some great case sellers on there!)
My only advice at this point, is to start with some of the merchants here:
http://www.digitalfaq.com/reviews/buy-dvd-cases.htm --- and if they don't have what you want in stock, ask for help from them. Not yet on that list is Polyline Corp and SleeveCity/SleeveTown.
These are all USA/Canada companies, of course. In Europe, many of the blank disc sellers have cases, too.
In fact, be sure to check Europe, if you've not done so. (Again, assuming you're in North America.) I've imported cases from Europe a number of times.
Again, good luck!