'Open Source' may have been too strong a term, I meant more like a variant you were talking about, in that they would retain some sort of rights over it, copyright would remain intact, but we would be allowed to continue developing it.
I moved away from classic only because I wanted it to work with some other software (gallery, etc.) and hated paying imagefolio ridiculous amounts of money for a script horribly supported by the authors. For sites without a lot of traffic, ubb.classic more than handles what's needed.