Dean Valentine, president of Walt Disney TV and Walt Disney TV Animation, is in the final stages of negotiations to take over the helm of netlet UPN from departing prexy/CEO Lucie Salhany. All of the principals involved in the talks declined to comment, but after an exhaustive three-month search, Valentine appears to be the one candidate embraced by both UPN partners, Viacom/Paramount and United Television/Chris Craft Industries. On Wednesday, buzz was swirling around town that Valentine had been offered the job and is eager to take on the new challenge of running a fledgling network after spending the past decade with Disney. The key obstacle now, according to sources close to the situation, is getting Disney chief Michael Eisner to release Valentine from the remaining years on his contract. Valentine is believed to have reupped for a five-year deal in June 1995 when he was given oversight of the studio’s TV animation wing.