So now that I am over the flu, I now have bronchitis. Which means I will have a few more days with my thoughts. I have been thinking about a Dark Sun one-shot or micro-campaign using Savage Worlds over the last few days. But, this this morning I asked myself if Dark Sun could be done with B/X? Sure, why not.
Changes would be intended to reflect the "feel" of Dark Sun but focusing on keeping things at the power level of B/X, focusing on archetypes as with B/X (even though these may be Dark Sun archetypes), and keeping the simplicity of B/X.
A few things I would do if I were to run Dark Sun with B/X:
1. Ignore the "its a brutal world so start at 3rd level" thing - and use 3d6 in order
2. Adapt the HP cost for casting spells from Microlite20 for magic-users and give them the option to instead of taking the HP cost themselves they can defile - each HP instead defiles X-feet of vegetation.
3. Psionics - dump them. Psionics actually weaken the themes and tension of Dark Sun, as they provide a safe alternative to magic-users, and they lack the whole "devotion to nature" aspect of the elemental clerics and the druids.
4. Remove elemental references from magic-user spells leaving fire, etc to the clerics - thus fireball would be removed but instead replaced with something like Eldritch Burst. It would have the same mechanics just different flavour.
5. Would have to redo the cleric spells into the 4 elements and would likely have to grab some from OD&D to build up the lists for each element (was there a Gaz or something that covered elemental magic?).
6. Grab the druid and ranger from OD&D - I wouldn't use a Gladiator - not different enough from a fighter
7. Come up with a Templar - what I would likely do is use the B/X cleric and spell list but give them a spell at 1st level and a cap of 3rd level spells
8. Redo the elf and dwarf. Maybe use the elf race as class as the ranger. Dwarf would be pretty easy - just remove the stonework stuff and find a mechanic for their focus. I would keep the halfling mechanically unchanged but add in the cannibal stuff.
9. Come up with the Mul, half-elf and thri-kreen - I would dump the half-giant. It infringes on the Mul's niche too much. These would also be race = class. Actually, the thri-kreen race as class should likely be the ranger.
10. Get rid of most of the exotic weapons but keep the idea that most weapons are not made of metal. Non-metal weapons become the benchmark (have the designated damage ranges) but break on a natural "1". Use "magic" to describe metal weapons - a sword +1 becomes a metal sword. Afterall, metalwork would seem like alchemy in a world like Dark Sun.
11. Monsters - get rid of most of the humanoid monsters but I think that the other monsters in B/X - especially the focus on "Lost World" type monsters - could give an interesting, if somewhat different feel.
12. Focus solely on the original Dark Sun box set for the setting.
That looks like a lot of work...
Honestly, I would probably be easier to do this with Swords & Wizardry or just use one of the Savage Worlds hacks on the net.