Facelets for PHP

Hi all, It is very likely that there is already a framework out there somewhere that does this, and that my searches are just too primitive to find it. Please bear with me. I would like to structure a site where every page is written in pure XHTML. In addition to the standard XHTML tag validation, I would like to reference a tag library that allows custom "components" to be added to a page. For instance: <form> <h1>Input here</h1> <myns:suggestionInputText /> </form> I would then like to use PHP to translate this into XHTML that can be sent as an HTTP response. Moreover, I would like to be able to define custom components using XHTML pages. The concept comes from Java Facelets. The main point here is that PHP generates a minimal amount of XHTML/JavaScript for each component, while the pieces are put together by running a PHP program against a pure XHTML file. Is there already a framework within PHP to do this, or would it require custom development? Certainly the possibly implementations are endless, and something like XSLT would be a natural step towards one. I am, however, holding out some hope that a framework already exists, and that I won't need to worry about this. Thank you, David