We used to have private messages enabled, but we had some pretty bad experiences with spammers sending out tons of PMs, so we had to disable it. Spammers ruin everything.
If you want to receive messages from other users, turn off the “hide your email from other members” option on the page linked below, and the “Email” button will show up below your posts, allowing other users to send you emails.
As far as the real question goes here, though, I’m afraid I’m going to have to second the suggestion that you don’t put the whole things online. Encrypting your source code doesn’t make a difference here, since what really matters in a template is the markup, which has to be delivered to a browser for the page to work at all. If your templates consist of multiple pages, you might want to consider giving a “live” preview of one of those pages, and screenshots of the other ones. If there’s only a single layout, though, a screenshot (or a set of them, if there’s multiple things to show) is probably going to be the way to go.
If that isn’t an option, enabling hotlink protection on your images will at least prevent people from linking to your template resources directly. It won’t prevent them from downloading and reusing them, though.
Enabling Google Page Speed may actually help a bit, as it rewrites HTML and CSS in a way that may make them more difficult to reuse. (Make sure to tell people that the code in the real product won’t be as ugly as in the preview, though!)