Have a look at http://tlc2.hg.sourceforge.net/hgweb/tlc2/tlc2/file/d68f1405e1c5/views/generic.xls http://tlc2.hg.sourceforge.net/hgweb/tlc2/tlc2/file/d68f1405e1c5/views/generic.xlsx
they use tablib (which includes xlwt, ...) http://docs.tablib.org/en/latest/index.html
