After having refashioned the TV Guide Channel in the guise of E!, Jeff Shell is leaving Gemstar to take the reins as the 1st programming czar at Comcast, according to sources close to the matter. In a conference call early Fri, Shell announced that he was ready to "take on a new challenge," although neither he nor anyone else at Comcast would confirm where that challenge might lie. "I’m not going to speculate on what I might be doing," he said, before adding, "It is definitely not official that I’m going to Comcast or anywhere else." The top spot at GMST will be filled by News Corp vet Rich Battista, the 3rd CEO appointed in the same number of years. — Shell’s defection had all of cable abuzz … and Wall St as well. A number of plausible scenarios regarding the future of Gemstar rattled through the stone canyons of lower Manhattan, and the stock market reacted with predictable volatility. Gemstar shares closed up 8% at $5.84 after Think Equity Partners analyst John Tinker said that he thought News Corp would buy the 59% of Gemstar it did not already own so that it can pitch the company to Liberty. Smith Barney analyst Niraj Gupta advanced a similar hypothesis, predicting that Gemstar "is likely to be sold to either News Corp or Liberty within the next year." Gupta reinforced his thesis by saying that Gemstar has "outlived its purpose as a publicly traded pure play," and that it’d be an "obvious fit" in Rupe’s fiefdom. The rumors may have helped nudge NWS a bit, as shares closed up 15 cents to $17.95. Liberty was essentially flat, gaining a penny to end the week at $10.78. — While everyone’s playing clairvoyant, here’s a pet theory we haven’t seen advanced by analysts: News Corp buys out Gemstar and then sells the company whole, or piecemeal, to Comcast, putting a nifty IPG in the MSO’s hands, as well as a few programming gambits. Another rumble on Wall St? Maybe so. Microsoft, which has a significant deal in place to get its proprietary IPG tech in CMCSA HHs, closed down a bit Fri, dropping 15 cents to settle at $27.08. Other Gems: Gemstar also named News Corp evp Anthea Disney exec chairman, a move that coincided with the resignation of Lachlan Murdoch from its board of directors.