In principle it is possible but I think it's a lot of work.
X2 uses a special format for the model files. The only 3D-programs that work with X2 are 3 DSMax and GMax. You have to import your meshes in one of this programs. Then you can export the meshes with use of DBox to get the X2 bod-files.
This is the basic outline of the steps you have to do. I personally can give you no help on the importing process of the meshes to GMax or 3 DSMax. Maybe there's someone else around who can. I know how to export the meshes from GMax and how to get the ships in X2.