What I tried:
#page-text {
background-image:
url(./images/paper-top.png),
url(./images/paper-bottom.png),
url(./images/paper-mid-2.png);
background-repeat: no-repeat, no-repeat, repeat-y;
background-position: 0 0, 0 100%, top 10px;
background-size: 100% auto;
}
Unfortunately the repeating part repeats all over #page-text and since paper-top is partly transparent, paper-mid-2 is visible in those transparent parts. For illustration notice the top corners of the paper (or see the live version)