I've been working on a falling damage system for 4e, since I find it unlikely that the default one will deliver what I want, which is a potential for both the cinematic, and the realistically lethal, without requiring a lot of dice and adding.
The problem with damage dice as a falling system is that in order for you to roll enough damage to outright kill a high level character, you need to roll a ton of dice. Especially considering that in 4e, characters aren't dead until -1/2 their total hp. Either that, or you need some sort of massive damage system, which is pretty much out of the question for my group, as they've made it clear that they hate that mechanic.
So here's my basic idea. Instead of dealing out damage dice, just use the defense score system to determine the result of the fall. When you fall, the ground makes an attack roll against your Fort defense. Yeah, I know, the ground making an attack roll is weird, but that's how 4e works. Here are the consequences.
Attack roll exceeds 10: Damage = 1/4 max hp (about 1 healing surge)
Attack meets: Damage = 1/4 max hp; Prone
Attack beats by 5 or more: Prone; Stunned 1 round; damage = 1/2 max hp
Attack beats by 10 or more: You are reduced to -1 hp, which makes you unconscious and you begin dying.
Attack beats by 15 or more: You're dead.
At 5ft, the attack roll is 1d20. At 10ft, it's 1d20+4, plus 2 for every 5ft (or 1 square) beyond that. So at 30ft it's 1d20+12, at 50ft it's 1d20+20, and so on. A natural 1 on the attack roll means that you do not die immediately, even if the roll still beats your Fort by 15 or more. This accounts for those weird instances where people fall 1000ft and still somehow survive.
If you make a successful jump or tumble check, the attack roll takes a -5 penalty. Some DMs might choose to increase this penalty even further if the jump or tumble check is exceptionally good, like a natural 20.
If the surface you land on is exceptionally soft or hard, the DM might choose to further modify the attack roll. For example: -5 if you're landing in deep mud, or +5 if you're landing on sharp rocks. Sometimes you may not want to roll for a 5ft fall, if for example the character is intentionally jumping the distance and there's no risk of him landing with his head on a rock or some other potentially disastrous scenario.
I might also introduce some feats that can be taken to improve the characters ability to survive a fall, and I'm sure there will still be items that help you survive long falls.
Keep in mind, this is an initial design run on this system, so it's not perfect. What is boils down to is, your first level character is not going to be jumping off 20ft cliffs and walking away unscathed unless you invest in the things it takes to be good at jumping. Even then, long falls like 50ft or more can quite easily kill low level characters, while still allowing the chance for survival. At the same time, as you level up, things get a bit more cinematic, and you can, with proper investment, make big action movie style leaps without a lot of trouble. Still, even a 30th level character can instantly die from a normal 50ft fall if they have no investment in items, abilities, powers, or feats that make them better at taking a fall (I don't care what WoTC says, some things actually
can kill you instantly

).