[NTLDR]

Find:

PHP Code:

if ($type == 'shout' && $comment_submit && trim($message) != '' && $bbuserinfo[userid] > 0) { 


Add after:

PHP Code:

$message = substr($message,0,CHARS); 


Change CHARS to the maximum number of characters they can use, any extra are just removed. Not the best way IMO, but the quickest and easiest

Alternativly you could do something similar to just reduce the text shown on forumhome.