In CSS3 two (or more) background images on one element is possible. But, since not all browsers support all of CSS3 yet that probably isn't too useful for you right now. Just something to keep in mind for the future though.
Thanks a bunch, didn't know that!
Now time to do some troubleshooting, my original style.css had this in it:
background:url(images/page-back.png) no-repeat top center #dedede;
Following the link provided about CSS3, I changed it to this:
background:url(images/page-back.png) no-repeat top center #dedede,
url(images/bg1.jpg) top left repeat;
Somehow this messed it all up - it doesn't show the original background nor does it show the second one (tested in Safari 3.2.1). Is it enough to just change that one line in the style.css or is there another place where I should add the new background as well?