I really like how FantasyCraft handles death. It has been a while since I have looked at the rules, but if I remember correctly, if a character dies, with DM permission and a plausible story a character can escape death at the cost of one of their prizes (and I believe a hit to Rep?), and come back with some persisting condition and are out for a few game scenes. Altho the system does allow a few of classes to grant free "petty fate" returns which essentially are the weakest conditions you can return with. The game also has dramatic scenes in addition to its standard scenes which follow different rules, and I believe one of them prevents characters from returning with this mechanic.
E6 has Death Flags. Essentially characters cannot die unless they raise their Death Flag, which grants them a 6 Conviction instantly (Conviction is the Action Points analogue of the system, letting them reroll dice or take extra actions a limited number of times per day). It is supposed to be one of those mechanics for more dramatic moments to give the players an extra push at a risk. It probably doesnt work all that well if the PCs cannot be challenged, which can be an issue in a 3.x game.
I usually run E6 with auto crit confirmation, so easy deaths are a concern, but I dont like or use the Death Flag rules. Instead, I added an option to spend 4 Conviction to prevent death for a round:
Spend 4 Conviction: If any damage or effect would result in death, Make a Fort save with DC 10 + twice Character Level of target inflicting the result (If none can be determined, DC 15) to set your HP at 1 point above death, and set any other condition that would normally result in death to a point just before being fatal if applicable (For instance, being reduced to 0 Con would set Con to 1). This effect applies across all such effects or damage sources for a round, but each addition source of death will retroactively increase the DC of the save by 2. This protection ends at the start of the characters next turn. The character is not considered stabilized, and must make checks as normal.
Ive only run it for a few sessions a couple months back, but it seemed to work out well enough.