Continous Voicemail/Text Message Notifications

I am trying to find out which AT&T handsets have an option for continous notifications of unread text messages and unheard voicemails. I currently have T-Mobile and a RAZR V3, which has a "reminder" option that allows me to have my phone ring or vibrate until I acknowledge the new messages and silence the reminders. I know there must be AT&T phones that do this - can anyone help me out with information?

Thanks!

as i know of only the att motorola phones do that. it is not the carrier that has that feature it is the phone itself. all motos att have do it