As gas prices continue to top $2 a gallon, all those drivers of fuel-efficient cars may not have reason to gloat for much longer. Oregon is worried that too many Honda Insights and Toyota Priuses hitting the roads will rob it of cash it expects out of its 24-cent-a-gallon tax. So the Beaver State is studying ways to ensure that "hybrid" car owners pay their "fair share" of taxes for the miles they drive. That means allowing the taxman to catch up to hybrid owners just as often as he catches up to gas guzzling SUV drivers. And if Oregon...