Special Relativity is just a coordinate system in which the one-way speed of light is defined to be isotropic. This coordinate system (inertial reference system) is convenient in that it can be realized today in any laboratory. An alternate coordinate system in which the one-way speed of light is defined to be anisotropic is just as valid as SR (when both systems are properly specified: see Y.Z. Zhang, Special relativity and its experimental foundations, (1997); http://www.worldscibooks.com/physics/3180.html).

wisp, I think that it is futile to try and make "a case against relativity" per se because relativity is just a coordinate system. Any valid "case" would need to stay focused on the actual experiment(s) needed to realize the alternate coordinate system described above today/tomorrow in any laboratory.