tl;dr Need suggestions for balanced resurrection mechanic for deadly deadly dungeon crawl. 
So.. yeah... I just found the tomb of horrors 
and having only skimmed a few "encounters" and just finished a little online reading about the horror stories about it and... well.. some of my players are at least a little attached to their characters. I'm thinking up a mechanic to make a "spawn point" so they're not just dropping their beloved characters into the cauldron and be done with it 
, and I have come to the forums for help/suggestions. 
My first idea was a neck item; it saps your strength and is a real burdon to have the option of coming back to life (perhapse having your soul in two places at once really sucks) but mechanically I was considering taking away the player's highest daily power and all action points as well as being a +0 neck slot item. Maybe it's a bit steep.. but for the power of ressurection at no cost? (Obviously it would work outside of the tomb, that would be just silly
) Perhapse a faction of the gloaming court (I think that was the associated good guys that sent you to it) has set up a temple and has figured out how to keep the souls of adventurers from feeding Azererak. (I don't think I would let someone survive the demilich soul suck tho) Any other/better/different ideas ladies and gentlemen?
Which brings me to my second thing. What should a spawn point cost? While coming back to life once or twice might seem like it should have the price of something comparable to raise dead, wasn't there a paragon power once upon a time that a cleric--or somebody like that--could resurrect somebody at the end of the next extended rest, if it was like the first thing they did, or something to that effect? I'm pretty sure I saw it almost a year ago but now the builder has nothing like that that I can find. 
I don't think I want to charge 500gp per head per death if they're going to try and stick it out. It's not worth it if they have to "pay to play" they'll walk away from one of the coolest dungeons of all time, because they ran out of ressurection funds! 
Yes I understand and admit there should be a penalty for death, but it should be A) the fun or B) the adventure. How do I balance.. death?
Basically; I live by the golden rule: It should be fun. Challenging yes, impossible maybe, but definately fun. Dying over and Over And OVER AND OVER 
And Over and over... I think I'd grow weary of it quickly. And making my players walk away from this awesome adventure would dissappoint me more than a little 
(plus I wouldn't really have anything else prepared for the rest of the day--I'm a student with precous little prep time)
Now, I plan on test running the "mod" 
at the casual friday table in a couple of weeks before I run it at my serious saturday home game (with a few weeks in btw the first and second run). I saw somewhere the S1 recommended running 2 characters simultaneously b/c it's just that deadly, so for the friday game I'll hand out a handful of pregen characters so everybody gets two PCs (theirs & an extra), and if people die at the casual game... well you get rezzed in LFR automatically anyway (stupid charity of friends clause) so what the hell why not. My home game on the other hand is more... realistic?... you get your items when you get your items and you have to deal with death straight up, etc etc right, so that doesn't fly well with me there. I HATE HATE HTEALHTOEIAHFEL
AAHHAAAATE contrived mechanics just because we need an excuse to do something, (we need an adventure for today; oh look an arbitrary benefactor posted a want ad on the metaphysical job post board; [adventurers wanted - wtp 50pg + 1 item inquire @ waddling duck ask for Bert] don't feel like helping bert? let's pack up and go home then. jesus f$c|<... where was I? RIGHT! There has to be at least a half decent plot point in place to justify a mechanic. Any more ideas/feedback/suggestions/etc? I'm all ears dear readers.
Your group's benefactor is... aware of the potential difficulties, and has supplied the group with a remarkable salve. It has a dozen uses (or so), and has the same effect as a raise dead scroll when used. This salve is a *rare* item, and as such, cannot be reproduced by the players.
Depending on how cruel you are feeling, the component cost can be included or not, in the salve's construction.
That protects them from anything but a total party kill.
also, 4e's tome of horries is much much much less deadly the 3.x's.
3.x's had "you died" in several places. As in "you walk into the tunnel, roll a new charcter"
4e's is doable without dying (though still difficult).