When it comes right down to it, if you are happy with the compensation for the effort, then make the product as well as you can. Who *owns* it would end up to be a matter for lawyers, regardless of contracts and verbal agreements (been there done that) so unless you have some technical concern about the number of sites I wouldn't worry about it.

Make nice code, you make money, the client makes money, everyone happy. And isn't that what it's all about?

EEjack