Any material that can resist the corrosion will be bombarded by neutrons until it is transmuted into another material that can't, even with "slow" neutrons.
The Wikipedia article[1] says, "A 2011 MIT study concluded that although there is little in the way of barriers to a thorium fuel cycle, with current or near term light-water reactor designs there is also little incentive for any significant market penetration to occur. As such they conclude there is little chance of thorium cycles replacing conventional uranium cycles in the current nuclear power market, despite the potential benefits." What did they know at MIT in 2011 that we don't? Or were they just wrong?
If really no material will work for this, I can only imagine some sort of mag-lev design that keeps the molten salt out of contact with other materials, but that seems kind of far-fetched.
If you were to build that, how would you transfer the heat out of the molten salt?
There are a bunch of places I've found where the difficulty (and therefore cost) of working with titanium is really holding humanity back. If we could find cheaper techniques for working with titanium it would revolutionize a lot of industries, as it's plentiful, light, strong, non-reactive, and melts at high temperatures. But the same attributes that make it hold up under the stresses of use, make it very hard to shape.