* Rome deciding whether to revive single network plan * Plan promises savings, but some favour competition By Stephen Jewkes, Elvira Pollina and Giuseppe Fonte MILAN, April 19 (Reuters) - When mayor Filippo Tripoli got a phone call from Telecom Italia last December to cable his town in Sicily he was taken by surprise. Bagheria, population 55,000, had already been cabled by rival Open Fiber and another network seemed extravagant. "It knocked me sideways," Tripoli said. "What's the point of cabling a place that has already been cabled once." Open Fiber finished work in Bagheria earlier this year and is now busy resurfacing the streets. Telecom Italia (TIM) has just started, but could be finished by the end of the year. Cost? Some 4.5 million euros ($5.4 million) for Open Fiber and around 3 million euros for TIM.