The use of thorium in the MSR is perhaps 30x more fuel efficient than the current light water reactor. Large amounts of thorium have been buried in the desert by the U.S. government. Also, sufficient deposits exist in the U.S. to support centuries of use.
As for nuclear waste, the real reason why the problem appears intractable is that nuclear waste is not waste.
The LWR gets only 2% or so of the energy in uranium, the same fuel could be reprocessed and used in fast breeder reactors to release the other 98%. In fact, it is the presence of plutonium and other actinides in spent fuel that requires environmental isolation beyond 500 years or so. If we use those actinides as fuel, they do not need to be buried, and if we do that, the volume of waste is vastly reduced along with the half-life.
The fast breeder/reprocessing route has not been commercialized as of yet for a number of reasons. Probably the most discussed is that plutonium, neptunium and other actinides useful for nuclear weaponry could be nicked from the reprocessing plant.
The thorium MSR is an alternate path to a breeder, aka a "thermal breeder". In the case of the MSR, the reprocessing is done online or nearline to the reactor. It is also possible to do thermal breeding with thorium with a modified version of the light water reactor. Reprocessing that is a bitch though...
The most immediate problem facing the industry is an inability to say "it is going to take X years and Y dollars to build a reactor" and then finish it somewhere near on schedule and on budget. Being over 10% would be no scandal, but it is still looking more like 10x than 10%.