Talks between Apple and China Unicom to bring the iPhone to China have come to a halt over demands by Apple, according to a new report. SinoCast reports that Apple was said to have asked Unicom to help pay for the costs of building special Apple storefronts across the country, after China Unicom agreed to a profit-sharing plan proposed by the iPhone maker. Executives at China Unicom would say that negotiations were ongoing, but refused to give any…