It looks like what you really want is to use a UITableView. It's the standard UI element to use in iOS when you have rows of data like you are describing.
Take a look at this link:
The UITableView handles the layout and formatting of all the rows / sections -- you just tell it what style you want, and provide some methods that it can call to get the actual data that goes in each row.
That doesn't necessarily answer your question about how to layout a long view in the designer, but it does solve the problem you are describing.
If you really need to layout a long view in the designer, I believe it is possible to temporarily change the size (height) of the view you are designing so you can see the whole length of the scroll view, and then change it back to the actual height before you save it. (At least that was possible in the previous version of XCode -- the last version I downloaded had a lot of things re-arranged and changed, and I haven't had the time to figure out where all the controls/options when to, much less figure out what doesn't work any more.)