We host about 50 domains on our server, but we have some customers that like to own ALOT of domain names, like owning example.com, but also own example.net and example.org so I make there primary domain what they want and then alias other others to the primary. Or in the case of one customer they have a primary domain name with a .com and then bought 151 domain names with different cities/states/countries ending it. So instead of having a interface like in 9.5.4 (we just made a leap in Plesk versions) of 54 domains, I now have an interface of 227 domains.
Thanks