What are your thoughts on addons and themes that want you to display author or website.
Some addons and themes require nothing but you install them to use them. Some want you to display a link to the author's website or the author's name. Wouldn't it be enough to leave the authors name in the source code than having to be an advertisement for the author. Does it give you second thoughts whether you will use a certain addon if that is a requirement. And the slippery slope - what if everybody who uploads an addon makes the request that you display there name on your site if you use their code or parts of it. Wouldn't this lead to a cast of thousands and you would need streaming credits like at the end of a movie.
Granted it is the authors perogative. But does it give you pause it this required.
I may not provide the completed solution you might desire, but I do try to provide honest suggestions to help you solve your issue.