If you go to the pattern tab on Ravelry, just underneath the search box on the left is a link to a tailored search. You can specify yarn weight, yardage, needle size, almost anything you'd like. Here's a search for a striped sweater in aran weight (Bernat Satin).
You can specify man, woman, or child etc. to further narrow the search if you wish.
Knitting Pattern Central is also a good resource but not so easy to specify search parameters there.