Apart from using a SystemCaller with a Template Zero row DBase File to File Copy/Paste, I can't see any immediate way of doing this easily in FME?
The dBase Writer doesn't have a Truncate or Delete option, so the only messy way I can think of is to instead write a SHP file with illegal geometry (this Writer Hack will then create the SHP and dBase files but pass over the Features with geometry not of a type matching the SHP schema and hence output a "Zero Feature" SHP file), and then deleting all the output files except for the dBase.
Any better solutions?