I'm right there with you (though bought my PRS-950 off Craigslist, NIB), also frustrated with the case/cover options. I live in a city and have visited 6 different stores looking for a cover that I like. 3 of those had ZERO options, for ANY ereader, 1 had Kindle 3 only, and the other 2 had the same option that I didn't care for. But I'll tell you that the Nook covers fit rather well (as is mentioned throughout the forums). The one that is available for the 950 is from Electronic Bookarmor. I HATE the design, but others like it (I desire something Far more streamlined) ~ it's worth looking at, it's neoprene and a Cover, not a sleeve.
I'm going to end up making my own cover to get the desired features/fit, I can just tell.
Best of luck on your search! And hope you enjoy the 950 (I'm 400 pages into a book in 2 days,

, no real complaints yet)