We bought this Thule for our two kayaks and it works well. Once you get the hang of using it, it takes very little time to load up. We didn't have any trouble taking it on the highway in terms of wind drag or wobbles.
http://www.autoanything.com/roof-racks/69A1847A0A0.aspx
http://www.autoanything.com/roof-racks/69A1847A0A0.aspx