Detectors based on the bulk-Micromegas technology exhibit position resolution better than 100 m m at counting rates of up to several tens of kHz/cm(2), along with trigger capabilities. These characteristics, combined with the detector's mechanical robustness and the possibility for cost-effective industrial production, makes them a promising candidate for the ATLAS Muon Spectrometer upgrade in a future luminosity enhancement of the LHC. The R&D project status will be presented together with the obtained results in the effort to define the baseline system specifications