well.....there is a way for doing such a thing...but it's not really a whos's apearing off line thnigy......it would go like this...if u have someones IP, and it's not dynamic IP, by certan ways u could technically check if the PC with folowing IP is online, but that doesn't mean that he is appearing offline on msn, he could be offline for reall
so that's all i can think of 'bout that........and 'bout the who block me scripts, u could do that! just make a script which will connect on ur other e-mail, and add all of ur contacts in other msn list and if they accept u could made a script which will check wich contacts is on line on one msn list but offline on the other...and that's possible ONLY if they accept ur other msn account...just a suggestion for those thing....
btw, sorry ;bot my english it sucks, and sory if i have just sayd somthing stupid above....i don't know anything 'bout this things