i do what denny does in that i have a keg of sanitizer [great for cleaning beer lines] and i pump it from keg to keg. what i end up with is sanitized kegs that have nothing but co2 in them. i usually only need 1psi or so to move the liquid and i have a short jumper that goes from beer out to co2 in. [that way i'm touching everything with sanitizer.]
when i'm racking from the fermenter, i do the sterile siphon like morebeer sells, only, i actually have a beer out ball lock on the end of my racking cane tube. hook the beer out to the keg and rack directly to the bottom of the keg via the dip tube. i unscrew the pressure relief valve to let the co2 out so the siphon doesn't stop. the lid never comes off the keg, so the only way that baddies can get in is through the tiny little hole where the pressure relief valve was. [in practice, though it is unscrewed, it still sits in the hole just so dust can't float down in there. this way its a virtually closed system.