Extracting text data from PDF files
Linux systems have pdftotext which I had reasonable success with. By default, it creates foo.txt from a give foo.pdf.
That said, the text mining packages may have converters. A quick rseek.org search seems to concur with your crantastic search.
This is a very old thread, but for future reference: the pdftools R package extracts text from PDFs.
A colleague turned me on to this handy open-source tool: http://tabula.nerdpower.org/. Install, upload the PDF, and select the table in the PDF that requires data-ization. Not a direct solution in R, but certainly better than manual labor.