It's been awhile since we last spoke, but not a lot has happened, so I guess that's okay. I've managed to read through a bulk of the old Dark Sun novels (though not all of them), as well as many of the original source books (I'd guess about 33% of them). All the while I had not been able to come up with a campaign idea.
Instead, I came up with what I believe to be a really cool campaign idea for a homebrew campaign, using the Nentir Vale stuff as a springboard. I've actually got a lot of ideas for that game, with specific encounter ideas and story arcs for all three of 4E's tiers of play. It should be noted that literally none of these ideas fit into Dark Sun as I envision the campaign setting. I presented this to my potential players as an option for when it came time for me to run, but it lost out to Dark Sun (though it was second amongst several options).
So Dark Sun it is. I do have a long-term story idea for the party. The goal will appear to be fairly obvious, but, this being Dark Sun, the end-game is not. I even have a story idea for the heroic tier. I'm still going to mine the 2nd edition adventures heavily for story and encounter ideas. I don't think, however, that I'm going to run the game straight through from 1st level to 30th level. Instead, we're going to skip around.
My current plan is to divide the game into chapters, spreading each chapter over 2-3 gaming sessions (we generally play for roughly 6 hours twice a month). Each tier will be maybe 3 or 4 chapters. This will give us a taste of the Dark Sun world at each tier, but save me from having to force story elements which don't fit the arc. Plus, I think the players tend to prefer paragon tier.
And we've already started. This past weekend (on July 2), I ran my first D&D 4E story-based game (I was able to run a one-shot encounter a month or so ago, but that's much different). We stated out at first level, and I ran the first half of my conversion of "A Little Knowledge" from the original box set. I think it works as an introduction to the world of Athas, though it has little connection to the overall story I have in mind (not necessarily a bad thing, in my humble opinion). Though there were no PC deaths, there was some hurting going on (it is either ridiculously hard to kill PC's in 4E, or it was ridiculously easy in previous editions).
As far as running the game goes, I was quite nervous about the whole thing, and very self-conscious about what I was doing wrong as a DM. I also kept second-guessing myself as to the toughness of the encounters and creatures I was running. However, the players were very forgiving, and I hear with time and experience one usually improves. It is because of this that I think running the Dark Sun campaign before my homebrew story is actually a good thing--the story for that game will be much better with (potentially) dozens of sessions worth of experience.