We could create you a skin that would look somewhat similar, but we can not give you one that is custom made for an existing customer. For demos - myself, other Clearpass SEs and the Local SEs will show different skins but those are ones that are for demo only.
As for the login there are features coming in 6.3 that will allow you to use Facebook, Google, Linkedin for guest login. If its an immediate need please send me a PM and we can chat off line about it.