We do quiet a bit of cobranding and I really think its a great way to go. Especially if you have a lot of traffic. Ours are def different and similar at the same time. I think its hard to build completly different sites. With webcams you have a lot of information and girls to show so it has to be built in a similar way.
You can see what we just did for sex key here
http://www.sexkeylive.com
Our main site is
http://www.tricams.com or
http://www.homesexnetwork.com