SBS has already hinted at an artifact that would do something like this. I believe it would essentially turn off the aging death and leave everything else active. Could keep a counter of how long you have lived past when you would die of old age and just give you a perma death on your next death or something.
They have also hinted strongly to Liches being a thing and also vampires. They would also of course have their own positive and negative effects but should also be immune to death from old age.
Not great at setting up links however but I'm sure someone else will.