PDFMod is an awesome little utility available in Fedora that allows you to split, merge and delete pages of a PDF document. You simply open a document up in PDFMod, and each page is shown in the interface, then you can delete individual pages, move the pages around (i.e. reorder them), import additional PDF documents, even rotate individual pages in your PDF.
This is an awesome tool to use in conjunction with Inkscape, as Inkscape can open, edit and export PDFs, but can only handle a single page at a time. A simple workflow would be to export each page of your PDF as a PDF from inkscape, and then merge them together using PDFMod. 
Máirín Duffy
We actually used that exact workflow you describe – Inkscape => PDFMod – to create the SELinux Coloring Book. 🙂