Not specifically a comment on 'Fair Trade', but as regards common standards for the issue of social and environmental compliance at factories, there are a number of efforts/options towards common or more widely accepted acceptance of various standards.
Within the apparel industry the most widely accepted are FLA, WRAP, the ILO Better Works Programme, and BSCI.
Platforms like the Euro-centric SEDEX and the US Fair Factories ClearingHouse provide the options for member companies to share audit results and promote cross standard acceptance in an effort toimprove visibility and reduce 'audit fatigue'.
In the case of WRAP, there are some 60+ brands and retialers between the US and UK which accept our social systems certification 'at par' to their internal & external standards.
Many brands/retailers also follow internal policies to reduce audit costs and compliance leadtimes but may not promote knowledge of the practice outside their organizations for a number of business reasons.
By far the largest effort currently underway is the GSCP Global Social Compliance Programme being driven by The Consumer Goods Forum. The Forum was created in June 2009 by the merger of CIES - The Food Business Forum, the Global Commerce Initiative (GCI) and the Global CEO Forum.
In the end all of us/you who work for brands or retailers can promote internally the acceptance of any/all robust compliance standards with a proven history and practices..like WRAP!