China plans to issue special-purpose bonds to lenders to help fund rural development projects and soak up excessive liquidity in the banking system, The Standard reported quoting the nation's banking regulator.   The country needs to spend as much as 20 trillion yuan (HK$19.5 trillion) to build roads, bridges and public services in rural areas by 2020, and banks are unwilling to fund the ventures as they believe they may be unprofitable, wrote the paper, quoted said Tang Shuangning, vice chairman of the China Banking Regulatory Commission, as saying.   He urged banks to lend more to rural areas, home to 60 percent of the country's population of 1.3 billion. "China's rural market is potentially huge and although it's still slumbering, it's about to wake up," he said.   Premier Wen Jiabao has recently made several statements to bridge a widening gap between rural and urban incomes that threatens social stability. US$1.25 billion is expected to spend this year to improve medical benefits for 450 million farmers and increase spending on agriculture by 14.2 percent to 339.7 billion yuan.