Cosmologist Marcus Chown says of the "Quantum Vacuum Intertia Hypothesis" work of Calphysics.org: (From http://calphysics.org/articles/chown2007.html)
"Haisch is perfectly prepared to believe that the rest mass of a particle - its mass-energy - is "explained" by the Higgs mechanism and that the rest mass is intrinsic to the particle. However, Haisch believes that the inertial mass and gravitational mass of a particle are not explained by the Higgs mechanism and are not intrinsic. If they are not intrinsic then there is only one other option. They must be "extrinsic". "In other words, they must somehow arise from the interaction between a particle and the environment through which it moves," says Haisch. "That environment can only be the 'quantum vacuum'."
This might explain why the Higgs mass is small. Haisch's theory suggests a mechanism similar to the Higgs effect, but relies on Zero Point Field Quantum Fluctuations instead of The Higgs Boson, and the Electromagnetic Quantum Vacuum instead of the Higgs field. But their work also tantalizingly suggests that Gravity appears to be the same phenomenon, but behaving differently in the presence of warped space-time.
So if mass (inertial, gravitational, and rest), is a function of either Quantum fluctuations or Higgs bosons, then it might be possible to manipulate not only mass, but also gravity.