You do not really need a domain name with a fix IP to connect to the VNC server. I have succesfully done VNC or X [not secure though] over dynamic DNS hosts i.e. even over phone lines. The only thing you need is the server properly configure and a way of knowing its IP.
I usually use the hostname:desktop_num_of_vnc to connect to vncserver. I also think it has no problem if you can get real IP through DNS server or hosts file...:wink: