Damn computer nerds...
To read and display a PDF file, you need a computer!!! Doesn't matter how many buttons, it still a computer, and needs an operating system. Have you looked at the PDF specification?
I bought a $50 GPS about a month ago, found the unlock instructions online. Now I can run Windows CE programs, including a PDF reader.
Now, as a student, I'd suspect you don't have thousands of dollars, or unlimited free time for this project. Yes, thousands of dollars, if you want to build it all yourself. Quicker and much cheaper to get a PDA, or something like a GPS to hack.