Good luck finding the mountain location plants! there is one nursery that will release a small number of them every now and then, and a friend of mine who rarely sells cobras but his are all seedgrown or divisions from his mother plant which is from a mountain location...and yes, in my experience, they are a bit more tolerant than the coastal origin/location plants, though otherwise are no different as far as looks go....
the problem in my opinion does seem to be keeping the roots cool, as well as good oxygen flow...these plants generally grow in areas where cold water from the mountains, passes through or over the roots...
though just as Joe above me said, i am also spoiled by my location, sharing the same zone and everything as the darlingtonia just south of me, so i have no problems with them what so ever...
i will say, that live sphagnum seems to be like the miracle worker with cobras...ive had divisions from my plant, planted in dead LFS, or peat/perlite that never do as well as my plant in live LFS, probably again indicating the oxygen available...
Would also like to point out the irony that the first 3 people to reply, are spoiled location brats
(all in the northwest where these things are easier than what they normally would be for anyone else)