I vaguely remember psicrystals holding the soul of the Psion upon death and escaping to a safe location to regrow a new body for its owner where the crystal itself is part of the new body. Was this done with feat or Class specific Psion?
The Psicrystal Imprinter PrC has this ability
The Psicrystal Imprinter gains the class feature Essence Crystal at level 9 (of the PrC, minimum character level 14) that does what you're looking for.
This seems to be, at least partially, based on the 3.5e Psicrystal Savant which gains Psicrystal Phylactery at level 7 (minimum character level 10... unless you cheese to Manifest 2nd level Powers early).