Funny,
I am working up a conversion also. I use the Athas.org stuff as a starting point (and I'm considering submitting mine to their project when I'm done).
But, you might not like mine:
1) I've never read the books, but I'm using my collection of DS game materials
2) I definitely emphasize 3E feel. I started with races and trying to balance the races (even Athas.org's) with the core rules is ridiculous. So I have decided to use a system like Monte Cook's racial levels (I need to ask Monte if it is okay to use the concept of racial levels, I suspect it is okay due to release of the core classes with racial levels by some of his acquaintances).
The statistics emphasized in DS are powerful and the abilities of certain races are way better than some feats. I just believe that game balance is as important as flavor. It is very hard to reconcile the two elements (and to know what to cut and what to keep). But I've done my best and I'm almost done with the racial levels.
My conversions emphasis is: Dark Sun feel balanced with 3E rules. Since there are many people who know the 3E rules, I want them to be comfortable. Then I want them to pick up the Dark Sun feel. I'll probably have to do a classes section, since I think those are out of line with the core rules as well.
-E