Roof Top Carrier

Does anyone out there know of a suitable roof top carrier for 2005 Hyundai Tucson? It has the factory fiited roof rack with cross bars. I've been looking at the soft sided type but it appears that they need to sit between the crossbars and require a gap of around 30", the gap on the Tuscon is less than 20". I could buy a hard carrier from Thule but I'm not sure it would actually fit onto the crossbars. Any help would be greatly appreciated.

Thanks

I have an XCargo I got from Sears years ago and we went back and forth across the country in our Escort wagon.  The latest version ast Sears:
http://www.sears.com/shc/s/p_10153_12605_02872020000P?keyword=xcargo&vName=Automotive&cName=Automotive+Accessories&sName=Car+Top+%26+Hitch+Carriers

That looks really good, are you sure it will fit a Tucson though?

No, but I'm sure if it doesn't, Sears will take a return.  I think they make those to be pretty much universal though.