Recently I am spending my free time on modeling a ship cannon in MoI and modo (still using 401). At this stage only modeling is finished and you can download the model for free here (non UV-ed and non-textured).
The UVed and textured model will be on sale on Turbosquid. It is available in modo 401 (.lxo) format and Lightwave .lwo format.
Warning the model in this phase is unoptimized, with no materials... just bare vertices and polys - that is why you get it for free. You can play with it and change it whatever you like.