There is no rule for peeing in any edition of D&D (that I know of). Maybe giving a fixed duration to the effect would be better, either 1 hour or a day. Also, 400gp seems alright.
I'm not sure where you're going with that. If the point is to disallow people from giving the circlet to one another, a better way is to make the circlet only give its benefit after it has been worn for a day (example: Mask of the Skull, Ring os Sustenance...). As it is, I feel like it's just asking to be abused with ability damage immunity.
I'm... not sure what the point is here. There's no rule for either smaller or taller than average character, and no mechanical effect for the effect of the bed, and the Mirror of Reversal is even worse, since all characters are assumed to be roughly symmetrical, the target of the mirror may not even notice its effect. I just don't know why anybody would craft or use these. They would probably be better if they had other unique abilities, like the bed removing any form- and size-altering magic, or the mirror also being able to reflect spells cast at it, or to act as a portal to the Plane of Mirrors. Also, how do you revert the effect? Is that a curse? Is that permanent? Does looking in the mirror again revert the effect? Do you need Dispel Magic, Break Enchantment? This goes for the Cursed version too. Depending on the actual effect, the cost would vary, but with only these "nothing-effects", well, 100gp is enough.
Items like that generally include a way to revert the effect. Not being able to eat again just cause you looked at it may warrant something like 10 to 15k gp at least, if a simple Remove Curse works, or higher if it requires a higher-level spell.
+1 is good. A fixed increase in price is more for something that doesn't interact with other abilities.
I like these. The price seems right too.
That's so tedious... Also badly defined. Do I need to roll to breathe mechanically? At each step I take? To talk? At each word? Sentence? Just to start talking? It's just weird and honestly seems unfun.
The +1 Str/12 level seems both arbitrary and a bit inconsequential. A level 20 character would just get +1. Maybe every 6 levels or 3 fighter levels would make more of a difference.
Seems a bit underpowered. You should give it another +1 to damage.
It's Maui time! The quest is a bit badly defined. Does it trigger when the character first takes the hook, everytime they grab it, or everytime they pull an island up?
Anyway, more to the point:
354: Spell Delaying Clock
This small hourglass can hold a spell and unleash its power after a few seconds to produce powerful combinations. When you cast a spell or spell-like ability with it in your hand, you may choose a number between one and five. If you do, the spell doesn't go off immediately, and is instead cast at the beginning of your turn after the chosen number of rounds. The target of the spell, square or creature, as well as any other variable, must be chosen as the spell is initially cast. If this target is not valid anymore when the spell activates, be it because the caster or the target moved so that the latter isn't in range anymore, or for any other reason, the stored spell doesn't activate.
Moderate transmutation; CL 7; Craft Wondrous Item, slow; Price 8,000 gp