I found myself using the StackPrinter application fairly often, so I wondered if it should be included on all sites. A tiny grey "print" button per question would be enough, and would quickly prompt the user to save the printed PDF.
If you are using a cool browser like Chrome or Firefox, you could use StackPrinter greasemonkey script.
If you are unlucky and your browser of choice is not Chrome or Firefox, you could use the bookmarklet (available on StackPrinter homepage).
Regarding the Trilogy request, thank you for that proposal but it's hardly feasible for two main reasons:
Anyway, It will be cool to try :P