In spite of the fact that the Keynote documentation suggests that it will produce handouts similar to the six-up layout that PowerPoint produces (three slides and three blocks of lines per page in two columns), it actually produces four slides in one column and then no lines in the other column. An example of the PowerPoint style is on the left, and an example of the Keynote style is on the right: The following trick improves on a combination of hints from the Keynote discussion forums and will produce PowerPoint-like handouts:
Export the presentation to PDF using the Print and Save As PDF... method, 1-up, with border. Call the PDF file presentation.pdf.
Load the lines.key presentation (attached) and ignore the complaint about missing items. Copy the one slide so that there is one for each slide of the original presentation. (These will turn into the little blocks of lines for the handouts.) Export the presentation to PDF using the Print and Save As PDF... method. Call the PDF file lines.pdf.
Use a tool like Combine PDFs to place one page of the lines.pdf file in between each page of presentation.pdf (or write your own tool with iText). Call the result result.pdf.
Load result.pdf into Preview, use Print and Save As PDF... with a 6-up layout to produce the final output.
This will produce output like the page on the left above.