No, that would be ugly and probably also not possible without a lot of work, as I am sure that the fx files are parsed directly using directx, where you then can only get the variables and techniques from and choose the technique you want to use from within the fx file.
What I mean is just a material flag like DOUBLE_SIDED or whatever.
On the other hand, there may already are all bits in use and I would like to see a better alternative for setting render states from outside the fx file, as flags would allow to combine the different cullmodes for example, which of course makes no sense.