stock rack enhancement?

I would really like to do an enhancement to the stock roof rack by adding a rail that runs parallel to the gulleys. The stock rack holds my surfboards very nicely, and the aftermarket racks I've seen would, at the very best, do no better and in many cases make the situation worse. If I added this rail, I would have the ability to ratchet a strap perpendicular to the vehicle in addition to the parallel strapping capability I now have.

Is there an aftermarket rail which would bolt right in?
Has anyone made a homebrew?
Will another SUV manf.'s rail fit if I found one in a boneyard?

I've worn out the search feature on several forums and have never seen this issue addressed. My apologies if it has and I didn't find it

agape,
robb