That just wraps text at some arbitrary line length and won't account for changes in listbox size or window size, which is what he's looking for.
It can be scripted using something like echo -mbflrti $+ $len($+(<,$nick,>)) $target $+(<,$nick,>) $1- however it doesn't work exactly right since the width of -iN characters won't correctly match the width of the characters used in the <nickname> format on a variable width font. Also the code I've pasted doesn't take into account the width of the timestamp, but that's a big headache of code to write so I left it out.
All things considered, a built-in option is the only way to do this practically.
