Hello,
This is a C# and 3D expert developer and I would like to offer my services to you.
I've already written parsing libraries for different 3D formats: 3DS, DAE, STL, STEP, OBJ and LWO. (As far as I can remember right now)
I would really like to also deal with the X3D format.
I guess you want a C# script able to load a X3D file into Unity3D, do you want to import the X3D file at design or run-time?
Best Regards,
David