We initially also wished to do netbeans development with vaadin 7, without having to use the maven stuff.
In Vaadin6 this was simple, it worked fine. But for Vaadin 7 we have not been able to do it in a reasonable way. So we finally switched to maven for the Vaadin7 projects.
You can install a nexus repository which caches the maven downloads, so it can prevent the timeout problems.
Not sure what the Vaadin Plugin actually allows you to do, but perhaps this one also works without maven?