Skirting material for bottom 6"

[Osogrande]

I have just purchased and installed a new double wide home in central Texas. Skirting with cement fiber boards (same as on the house sides) was included in the price. The contractor said he would mount OSB on the metal skirting frame from the bottom of the house down to the ground, and then install the cement boards onto the OSB. I objected that the OSB should not touch the ground because of moisture and also because of providing a superhighway for termites into the house. Also the cement board manufacturer said their boards should be a minimum of 6-inches above grade. The contractor doesn’t have any acceptable alternatives. Since I’ve already paid for the board treatment, I’m just looking for options to fill in the bottom 6-inches. I have considered other alternatives, including some composite board like Trex (expensive and questionable performance), boards made of PVC (expensive), metal flashing (concern about looks and eventual rusting), aluminum soffit or fascia, faux stone (don’t think it would look good next to the cement boards), and even Galvalume (expense). Other options like a concrete footer seem like too much trouble since the metal frame is already installed. I'm out of ideas, folks, and would like your assistance to think this through.