My statement about the character limits was incorrect and ambiguous. Git-cola is similar. It displays the number of characters and a color. No color for up to 64, yellow to 72, orange to 78, and red above that.
The body wraps the next word onto a new line if it crosses past 72 characters. (By default, that is configurable and disable-able)
Those are fairly arbitrary choices, but they work well enough for me in practice and help keep my titles/messages clean and readable.
If Fork could do something similar (the auto-wrapping and title warning) I'd be happy.