Frames rarely solve problems, but most of the times, they create a huge load of new problems, starting with breaking bookmarks, search engines, and page designs. The same applies to iframes. Don't use frames and iframes for new web pages.

The OP wants a showcase effect. I can't imagine any good use for that. Javascript code to break out of foreign frames had become common just because people don't want to see their work in a showcase of some bad guy that pretends it's his work.

For a web designer wanting to show his work, standard hyperlinks to his client's web sites should be sufficient. Adding a target attribute to open a new window or tab may be useful, but is completely optional. A simple screenshot is often sufficient, too.

For web sites that want to share content on the base of some kind of contract, parsing and rewriting HTML and JS should not be needed. The source web server simply offers an interface from which the content (and required meta-data) can be fetched in a form that is easily useable for the showcase web server. JSON and XML could be used as data formats, FTP and HTTP could be used to transport the content and meta-data. Passwords, SSL certificates, and IP address checks could be used to limit the availability of the data and meta-data. Transforming the content to (X)HTML is left to the destination web server.

Alexander