Please check out a new test server for PDF generation hosted by PediaPress. It is using a new renderer, we have been working on for quite some time and allows you to create multi-article PDFs. Currently, you create a collection from one of the following projects: Simple English Wikipedia, EN, DE, ES, FR, IT, NL, PT, and SV Wikipedia. Other projects can be added as well on a per-request basis. After selecting a Wiki you can start adding articles. Open https://pediapress.com/collector/ again to select a different wiki.
Please note that this project is still in alpha-state. This means that we haven't tested too many articles and the rendering of an article might fail for non-obvious reasons with no clear error messages.
Also, rendering is far from perfect. You will very likely find lots of things you don't like (but maybe also a few things you do). Please share your experiences and let us know about the most glaring problems you encounter.