Verizon and Vodafone are considering a shift in ownerhsip that could shake up the cellphone industry, a rumor claimed this morning. While Vodafone already owns a stake in Verizon, the two are aiming to change the financial relationship and may include anything from a dividend payout to either a complete spinoff of Verizon or even a full acquisition of the American carrier by Vodafone. A BusinessWeek tipster said a decision isn't yet close and may hinge on Verizon paying off its debts from taking over Alltel last year.