I've seen some cgfx code along the lines of: int var[] ; Is it possible to do something similar in HLSL? I'd like to know if its possible to have dynamically sized arrays for effect parameters. (I'm not sure if the above cgfx code is compatible with the directx profiles)

No such concept exists in HLSL. You have to do something like this:

float4 vals[MAX_VALS];int numVals;for(i=0;i<numVals;i++){  float v=vals;..}