I'm looking for something equivalent to SelfControl for the iPad. Is there anything like that?
Are you referring to the self-discipline-enforcing mechanism like this one? That is: something that notices that you are spending a lot of time doing various things that you don't want yourself to do (too much web browsing in general, or perhaps too much Facebook in particular, or too much email...?).
If that is the case, then it is difficult to imagine how something like that could be written using the official SDK that Apple provides, because you would need to modify Safari, or block IP addresses, prevent other apps from launching, or some such thing. These are not things that the official SDK allows a software developer to do.
Perhaps there is something in the world of jail-broken devices, but I can't speak to that point since I have never ventured into that territory.
Weblock blocks ads, but can also block distracting web sites, like Twitter or FB. As far as I understand, it will also block access for apps. Unfortunately, there is no option enable access for some time, like in SelfControl.