loophole in the GPL?

[Justin Wells]

I'm sure it's not, but someone please explain to me why not. 

If the GPL is just a grant under copyright law, and not a contract, then
why can't I do the following:

  -- I get a copy of a GPL'd work called "SSP" (some software program)

  -- I am legally entitled to make private derivative copies of such a 
     work, and I am the owner of those copies. So I make some changes to
     the work, and then I compile it, producing a binary.

  -- The binary is a copy which I am legally entitled to own, and I have
     the implicit right, under copyright law, to sell any copy of a work 
     I own to someone else--nobody can take this right from me.

  -- I sell you the binary copy, without giving you the source code. The
     GPL is not allowed to prevent me from selling to you the copy of the
     binary which I legally own. 

  -- I make lots of these copies and sell them to lots of people, never
     giving anyone the source.

The GPL says that if I "distribute" copies then I must provide source. I,
however, maintain that I am doing no such thing--I am *selling* copies,
transfering my ownership of that copy to someone else, not distributing 
them.

This wouldn't work if the GPL forbade me from making my own private 
derivations and privately copying them. But I don't think it forbids 
this: it lets me privately do whatever I like. And once I've privately 
made a derivative, I don't see why I shouldn't be able to sell it, since
copyright law insists that i have the right to sell any copy in my 
posession.

Justin