THis isn't exactly what you were looking for, but back when I had a DSL connection I used something called dns2go.
Its a free service where you install a routing program on your computer (tiny as hell) and it basically connects to the dns2go server, then updates your IP in its records.
So you can make a "domain name" for yourself like say, "halo.d2g.com" so that when people want to log into your FTP, they go into ftp.halo.d2g.com.
Now even if your computer gets disconnected, as long as it reconnects on its own, it will log back into dns2go on its own automatically and rebuild the connection.
This is sweet too, because if someone is fucking with your FTP, or you run a website and the heat starts coming down on you, you can just turn off the dns2go forwarding service and boom, they can't touch you.
It should be found at http://www.deerfield.com