Even if the size is increased the problem is only reduced, since there will always be users with too long names. Although it wouldn't hurt to allow slightly longer names imo.
Truncating the names to the max size would be a better solution in my opinion. For example, if the max size is 10 and your profilename is "I_have_a_really_long_name" it would be truncated to "I_have_a_r" and thus not messing up the layout.
I'm guessing there aren't a fixed max size, and that the "graphics-stuff" inserts the newline automatically when the name doesn't fit on one line. If so, then the max size need to be pre-determined, by investigating how many characters that fits on one line (using only the widest character in the font, 'W'?).