With Paramount and Warner chasing Time, Hollywood seems to see a raider behind every tree these days. Earlier this week, for instance, several agents and producers were sure that Wall Street giant Carl Icahn was preparing to launch a new movie company called Arbitrage Productions, to be headed by former Imagine Films Entertainment president Tony Ludwig and producer Lee Caplin. "We're really not. We're not going to do anything at all," a source in Icahn's Mt. Kisco, N.Y., office insisted Tuesday. The individual, who declined to be identified, said Icahn briefly considered a fling at movie finance with Ludwig and Caplin--but only if he could put just 10% of his own money down to match guarantees from foreign buyers and studios covering 90% of the production and marketing budget for films in the $15 million range. Apparently, some friends at the big studios persuaded Icahn that it couldn't be done, although the financier is supposedly leaving the door open to individual projects if the terms are right. Icahn, who is worth about $1 billion according to Forbes Magazine, turned big profits in past years by buying and selling large stakes in Viacom and Gulf + Western, as Paramount's parent used to be called. Ludwig and Caplin couldn't be reached.