Well, I believe that Korah mirrors the opinions of most with respect to public domain. We encourage the seeking of permissions, but do not lay demands to that respect, because the designs being used are copyrighted by Paramount, and the modeler did not receive specific permission to use thier design to make a model for release, free or for pay.
Now, one point I would like to make, is that selling models is hardly illegal. People sell them all the time. I pay for models that are based on my concepts, and I would like to see some company try to lay copyright on the designs, considering that they came out of my head
EXACT copies of copyrighted material, or models that would violate intellectual laws, would not have rights with respect to restriction of usage. If you design a varient of the Soveriegn for sale, and you do not call it the Soveriegn, you are certainly within your rights to sell it. It can also be said that the name does not have a specific copyright, so you could even sell a version of the original work, as long as it was identical to the original. Imagine if every vehicle manufacturer would have to pay copyright usage to Ford for inventing the automobile! There is a certain level of flexibility here. As long as your practices do not limit profits for the copyright company, they will usually allow it.
..........but they do reserve all rights.
Also remember that there are lots of modding products out there that were not authorized by the original game designers, but are sold for profit anyway. Quake editors in particular spawned sales of the game long after the released version lost its luster, increasing total sales for ID.
I think that a cross program is a good idea for model making. We are already developing a product for that, a version of Milkshape that will import Armada, BC, SFC and KA models for alterations. The program is open source, and will have to be reviewed by Chumblasoft before release.
Companies recognize that modding increases sales, and keeps the programs popular, opening the way to new version releases for profit that are not as dependant on market fluctuations.