To me this is an obvious copyright matter.  It doesn't make any difference if you're selling the result or giving it away for free, and it also is not right to assume moral high ground just because a lot of other people ignore copyright law when doing this kind of work.  In its simplest form, copyright is "the right to copy", which is always retained by the originator.  I may own this mesh, but I do not have the right to distribute it (provide copies) because it is an obvious derivative work from the design in the game - that was the whole point of the project!

This is all very basic application of copyright law, although many people ignore it because they find it inconvenient or they simply can't take the trouble to look into how it works.  As you noticed, they own (they hold the copyright to, more specifically) the likeness from which was derived - this means I cannot distribute the mesh however I wish.  It is not complicated*. * Fan art is not exempt, it's just that this aspect of the law is so commonly violated that it's hard for all the wronged parties to enforce it.  That doesn't mean it's legal or ethical to distribute derivative works in the name of "fan art" without permission!

http://www.copyright.gov/circs/circ1.html#wci

What Is Copyright

Copyright is a form of protection provided by the laws of the United States (title 17, U. S. Code) to the authors of “original works of authorship,” including literary, dramatic, musical, artistic, and certain other intellectual works. This protection is available to both published and unpublished works. Section 106 of the 1976 Copyright Act generally gives the owner of copyright the exclusive right to do and to authorize others to do the following:

• To reproduce the work in copies or phonorecords;
• To prepare derivative works based upon the work;

[...]
 

So yes, you simply do not know wtf you're talking about (meant in the friendliest way possible). :)

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