Creating a White Label Solution

Hi Guys, new to the site. So please excuse any noobness.

I'm developing a directory which I'd like for my customers/affiliates to white label and use under their domain. I know there are issues with duplicate content, but does anyone have suggestions on the best way to do this WITHOUT hurting my customers domain? One idea that I have would be for them to create a subdomain themselves and just have them point that subdomain to my servers. The other idea would be to just have them go to subdirectory from my domain, but i'd like to stay unknown to their customers.

This is not an SEO play for my customers it's really just to have another value added service that they can provide to their clients.

Thanks in advance for the input.

If it's about webcams white label check how Bomgacams are doing it, the SEO part i mean

Thanks Dante. It's not about web cams, it's a business directory. But I'll check them out.