is there a way to control the size of the Infobox?
No This is a static control that is like the Office notification windows...what you could do, though, is create an info that InfoBox that comes up with the number of errors, and then what we do is have a link that appears on the dialog that they can click and view all of the broken rules...in our medical app they can even click the item and it will take them to the field in question.
Then once they click the link it presents the following window:
Then if they click any of the links (in blue) it closes this dialog and automatically navigates them to the appropriate control.
This is just the approach that we took, but I thought that this might give you an idea or two. Hope it helps.