Sorry I didn’t get this out sooner, I’ve been swamped with work lately. This is not the most graceful solution, I’d like to revisit this in the near future and develop a more robust and customizable implementation. Anyway, here’s what I did. I’m using the MODx API Library to query the database and get the Long Title, Intro Text, and Content of the current page. I’m also using an open source HTML to PDF conversion script http://sourceforge.net/projects/html2fpdf/
1) Download "modxapi.php" MODx API Library file from respository at: http://modxcms.com/extras/package/286
and copy it to the installation directory of your modx site (this is also included it in the zip file).
2) Create a folder called custom under the root directory of your modx site and copy the folder "html2pdf" into the custom folder.
3) Create a snippet called "CurrentDocID" and paste the contents of CurrentDocID.snippet.txt into the Snippet code (php) box.
4) Insert a link to the create_pdf.php with the "docid" parameter equal to the current document’s ID into a template or in a document.
Example: <a href="custom/html2pdf/create_pdf.php?docid=[!CurrentDocID!]">Save as PDF</a>
Note, if you decide to put the html2pdf files in a different location, please make sure to update the path to modxapi.php on line 3 of create_pdf.php.
Hopefully this is helpful.