I'd just get a straight pattern to work from. Most sweater patterns are knit straight, so you shouldn't have a hard time finding a good pattern.
If there's a particular stitch pattern you want to incorporate, let us know, and we can help you translate it from circular to straight needles.
Hope that helps,
KnittingHelp Queen Bee
It is not because things are so difficult that we do not dare; it is because we do not dare that they are difficult.