Mind you, said price can't be too steep. Madness points are supposed to ultimately be a good thing, remember. As much of a good thing as any reward for slowly losing your mind can be, anyway.
There's one other consideration when coming up with these rules of which I remain cognizant: simplicity. If I overly complicate the rules the player who dives most fervently into these madness rules will let me hear about it. He's a big fan of simplicity, not because he's lazy, but because he thinks overly involved rulesets detract from gameplay and, ultimately, are stupid. He still touts red box D&D as having 14 pages of rules and being a complete game unto itself. We argue over "complete" all the time, since he says filling in the gaps is a GM's job, but that's not a discussion germane to this post.
So, bad but not too bad, and mechanically simple. That's a pretty broad set of parameters. What can we do with that.
After much pacing and conversation with Boaz, my dog, here's what I've got: Boaz is very supportive but not a deep well of ideas. In the end, his contribution was a request for a belly rub. As for the game, I'm thinking that madness points have two stages to them:
These are the unspent madness points. Until they're spent they don't do anything. They just sit there. If you never want to use them, don't. They won't hurt you. The way I figure it, these are the things that take a little of the edge off the pain of suffering a madness attack. If you're willing to suffer those penalties without reaping anything for the bother, that's bad enough. So hoard your points all you like.
The Grip of Madness
Once you spend madness points, they go into a separate pool. Put them in a cup or a bowl or something like that to separate them from the unspent ones. This represents the downside of the madness rush that granted you a bonus. If the 1k1 bonus they gave you on a roll is like an adrenalin rush, the grip of madness is like the weak, trembling comedown off that rush. You will overcome this eventually, but in the meantime it eats into your capacity to function.
Every time you roll a drama die, remove one die from the cup. Don't roll it, just take it out. That drama die doesn't explode. Note that you only reduce the madness dice in the grip for rolled drama dice, not drama dice spent on sorcery or swordsman techniques. If you don't roll the die, and thus don't have the opportunity to see it explode, this penalty isn't a penalty, and thus doesn't apply.
You also remove one die from the grip each time you roll a 10 on any other die. For each normal die that comes up 10, take one madness die out of the grip and throw it away. That 10 also doesn't explode because of this.
Once your grip is empty, all of your dice explode normally.
Now, there's one other part to this that I should note, because it's a way around the penalty for being in the grip of madness: spend a madness point.
That's right. Any roll in which you spend a madness point, and thus tighten the grip, you're not subject to the penalties of the grip. Sure, it dooms you to a spiral of accumulating and spending madness points until you're largely incapable of accomplishing anything but the most basic of tasks without resorting to that gibbering strength you've been cultivating, but hey, that's voluntary insanity for you.
It's important to note that madness lingers. This means that your madness pool, along with your grip, carry over from session to session. So there's no sidestepping this penalty by hoarding your madness points all night and then blowing through them in the last few rolls of the evening, filling up the grip right before packing it up for the night and then starting the next session with a clean slate. It doesn't work that way.