Being small, Vietnam doesn't show up on the accompanying chart at right. If the Market Vectors Vietnam ETF (VNM) were on the map, it would be the 2013 leader. The ETF is up about 18% this year. In the stock market today , 'Nam stands as a high-potential, high-risk trade. So while conservative income investors probably shouldn't be buying it for the dividend that yields 1.8% on an annualized basis, aggressive growth investors may want to look