Configure ssh access to router ... possible without domain name?

The only way I can find to configure ssh on a router vty is as follows

crypto rsa generate rsa
line vty 0 15
transport input ssh

The problem is that the crypto line cannot be entered without having

ip domain name <domain>

which is not part of our standard config. (Before anyone asks, we use
ip domain lookup to specify the domains to search on the box itself;
and we prefer to not have a domain name in order to stop it appearing
in CDP, and management systems. All our router names are unique so we
don't need the domain name.)

It seems we can configure a domain name, generate the rsa key, then
remove the domain name; or we can set a short domain name - such as a
dot(.). Either one works .... but is there a way to avoid this? Any
guidance appreciated. FWIW the following link applies <http://
www.cisco.com/en/US/customer/products/ps6350/products_configuration_guide_chapter09186a00804fdef2.html>

.