Suggestions for most efficient way to create a second app or site with minor rebranding

I've been asked to create a new Foundation 2010 ite that's going to be 90% the same site as one for another division. The current website uses custom masterpages and some other customization. My understanding is that the differences are going to be a different URL and some minor branding stuff. THey are external presence sites. I don't believe it's using search or much else in the way of services, custom wsps, etc. Very simple sites.

I'm thinking of backing up the dbs, restoring using different mdf/ldf and db names, creating a new app and attaching, but not sure if the GUIDs will conflict. I'm also thinking that what the masterpages call in _layouts may need to be changed, which should be pretty simple.

Anything I'm overlooking?

Also, apologies for using apps and sites interchangeably, I'm aware of the differences. I was actually asked to create a new site and assign a new URL to it, but if that's doable it sounds more complex to me.

Thanks,

Scott