Timestamp Plugin for Wordpress comments required

Hi, Need a quick wordpress plugin which allows any user (when making a comment), to specify the date and time of a comment (i.e. so he is basically defining his own timestamp of his wordpress comment). Obviously you need to make sure that a user can't select an invalid date, for example, 30th Feb 2010, etc... Will pay a quick $15 to $30 for this. You will need to test this on your own wordpress installation. I prefer to install the plugin myself. Thanks.