In fluorescent lamps: The only way to get rid of the liquid mercury is by using an amalgam like in Megamen CFLs and our Hyundai Teva helical CFLs that also uses instant on amalgam technology (And as a bonus, the lamps will run at optimal efficiency at higher temperatures).
In HPS lamps: Getting rid of the mercury is very easy: A higher pressure xenon buffer (300 torr) inside a longer and narrower arctube, with an addition of an antenna to facilitate ignition on standard ignitors (And as a bonus, the lamp will last longer [30,000 hours], will have much higher efficiency and wouldn't cycling).
In MH lamps: Getting rid of the mercury isn't possible, as this will require a new type of ballasts for them as they wouldn't retrofits on the current MH, HPS and MV ballasts (Nor reactor and nor CWA pulse or probe start) because their electrical characteristics will depends on their halides chemistry and not on the mercury.