Luther and Kor Phaeron are good examples, but they were upgraded 10.000 years ago, while the Emperor was still alive - while geneseed was still understood fully..
How long can an average human live if he gets augmentations in 40k? I know that some of the warmasters (macharius, slaydo) easily lived beyond their hundreds
As i said earlier, Inqusitor Lord Hector Rex and the one from the Soul Drinkers show humans can become very physically powerful, even without Space Marine augmentations.
As to life spans, wealthy individuals or those with access to the right stuff can live for centuries. There's juvant treatments, bionic replacements, sheer psychic will power and who knows what else. There are some Magos's of the Mechancius who can extend their lives for millenia, though their minds decay.