I have some 8.5 x 11 PDF documents that are the "left" and "right" pages of what should be a 11 x 17 document. I am looking for a way to combine/stitch these files together. Either a Windows or Mac solution is acceptable.
Most solutions I find seem to merge these two single page documents into a two page document, and not combine them side by side into a 11 x 17 larger document.
Additionally, I'd prefer the solution to be "free" and "easy": "Free" meaning I'd rather not buy a commercial product and "easy" meaning not having to download and compile a set of command line tools.