Lots of stuff to reply to! I'll be brief.
@David. I've looked at Zendo, and I'm pretty sure that's not what I'm going for. I mean, I don't know, I could be wrong in my own assumptions. But my gut is telling me no.
@stefoid. Dear gods, no. I'm definitely not doing that. That's partially why I'm iffy on zendo, too. It sounds too much like "figure out the GM's clever plot!" to me.
@Chris, exactly. ToC doesn't make you work for the clues. Which is - to me - essentially a way to make sure the players will get to the end. CoC makes you work for the clues themselves, which (I think) factors into how well prepared you will be for what awaits you. I'm interestend in zooming more on that.
Roughly, it would be like this:
*GM, your job is to prepare: something bad happening, the people and/or monsters responsible for it, a (first) effect or evidence of something bad happening.
*Players, your job is to see if you can figure out what is happening, and who is responsible.
It's not "discover what's going on and then decide what to do about it". That would be like Dogs. I'm certain to discover what's wrong with the Town in Dogs, since the GM's job is to reveal the town actively in play. In Dogs my job as a player is to decide what to do about it, not investigate the mystery.
I'm not interested in the "what do you do about it?" bit! As I pointed out above, once a mystery is resolved, it's often painfully obvious what to do about it. When you find out who the serial killer is, you don't ponder about it, you lock him up! When you know who's the werewolf, you shoot him with a silver bullet, the END. (this of course provided that I'm not interested in getting gripping fiction or thematic narrative from it, it's not Story Now)
Now, to fully ebrace a Step on Up investigation, I guess there must be the "can you" element to it. I think this is the biggest design challenge here.
David, you wrote:
"When I fail to find information, for the love of god, kill me, don't force me to meander about in confusion! (Or make me trade hit points for info or something.)"
Yes! In a fight, it's pretty obvious when the PCs have lost (or "lost") and need to run away, back down, give up or die or whatever. "Try harder next time." How to make failure not terrible?
How do you know that the players have failed to resolve the mystery? You can't leave them flounder about in the dark, pointlessly doing stuff that has nothing to do with the mystery. When do you say "Ok, guys, I think you can't figure this out, game over?" That's the questions that need answering.
1. I think the simplest and most obvious way is to have one or more progress tracks or countdowns on the table, clicking to inevitable conclusion. CoC handles this well with its Insanity meter, of course. You go insane, insert coin. ToC, too, but I think ToC's motivation for the insanity meter is different than CoC's (intentionally or no).
2. To use Storming as an example again, if I have my character chat up the barmaid or weave baskets instead of going into the dungeon to kick the monster's ass, then I'm playing obstructively. I'm not playing where the game is. My hypothetical game would need simmilar methods of positioning and player direction to keep the characters focused on the task at hand.
(I thought I would be writing this game this month, but I'm currrently caught up in writing a Spartacus game and trying to study, so this will have to wait.)