This isn'an a question, just a results log on an issue I had with XCode 4.5 storyboards and dynamic height UITableCell with a UILabel.
The issue was; the initial display of a cell would only show part of the resized UILabel contents, and that the visual UILabel was not resized. It would only display correctly after scrolling off the top of the Table and back down.
I did the calculations in hieghtForRowAtIndexPath and sizeToFit the UILabel in rowAtIndexPath. The sizes where coming up ok in debug, but the device was not updating the display with the correct size and UILable.text value.
I had created the dynamic UITableCell in a storyboard. However, I had set the width and height to a nominal value (290x44). It turns out, this was causing my issues.
I set the width and height to zero (0) in the story board, and everything started working correctly. (i.e. the UILabels displayed at the correct size with full content).
I was unable to find anything online on this issue, except for some references to creating the custom table cell with a frame of zero. Turns out, that was really the answer (for me).