Does any one have any good ideas about building kayak saddles for the top of my car?

I have been getting by with foam padded Yakima bars. They have been fine for short trips but I would like some thing a little more secure for longer trips.

I could buy the Yakima ones, but for two boats that is $160- $220. I could almost build another boat for $200.

Does anyone have any cheaper suggestions?

All thoughts are appreciated.

CHad