Does Dynadot have such a feature, or has ever considered adding the following feature? 1. Ping a specific website every X minutes. 2. If the website ping does not return for Y times, to send an automated e-mail to a specified e-mail and/or SMS recipient.
You have to put a simple file on your site and they check every fifteen minutes to see if it is there. I've used them for at least three years with awfuly good results.