Why not count on the good will of everyone and have a subforum called 'Inspired from...'?
So that the OP can clearly state what project hers/his is derived from.
Obviously, every designer that is going to propose something very similar to another project knows what (s)he is doing.
If (s)he is not or if (s)he is not honest enough to admit it, then a mod should move the thread to this subforum section. That could be a 'way in the middle' between a ban/remove and doing nothing.
And if the OP doesn't agree with such a move, then it's up to her/his to specify what is different in her/his concept in comparision to the 'orginal' idea.
And that would maybe let the possibility for the people who did the original work to agree or not with these being real changes, and then asking or not the mods to close the thread.
I think that could be a way to allow the cloning behaviour, why still clearly showing to the world that it is a clone project. Users will then be free to do what they want with it, i.e buy the product or not.
Just a thought...
