From the SRD : "While item creation costs are handled in detail below, note that normally the two primary factors are the caster level of the creator and the level of the spell or spells put into the item. A creator can create an item at a lower caster level than her own, but never lower than the minimum level needed to cast the needed spell."
The lesser and greater versions are good.
Seems better that way. Honestly just leaving it as is to the DM and rules-lawyers to decide whether combining the charges is possible is not bad.
We'll be following your carreer with great attention.
I like it. The examples are detailed enough to give an idea of what to expect of other uses.
Typical obyrith lord SLAs. PAO is strong. With 20th level cleric casting, Obyrith perks and form of madness, it may be higher than CR 24. Maybe 25 or 26.
Does this require a Sunder attempt? Or to specifically target the tentacle? Does the Queen take the 15 damage?
How is it different from Constrict? If it's not, then add it to Constrict. If it only affects one creature, then say "one trapped creature each round for ...damage", rather than "a trapped opponent for ... damage each turn".
Use a sentence. "Once every hour, the Queen can exhale a cloud of noxious gas in a 30ft cone obscuring vision as deeper darkness and nauseating creatures as stinking cloud (Fortitude save DC 26). The DC is based on Con."
Can the Rod actually be used if it is not fully assembled? Maybe make it so that the Queen can open the Gate every time a new fragment of the Rod is assembled. Why does she not simply steps through herself to absolutely destroy the poor PCs who found the first and second fragments? Is she bound to her realm somehow? I don't have the courage to read the whole Rod of Seven Parts adventure book just to find out. I'd say she fears the power of the Rod itself, even incomplete. It has the power to make things act more Lawful, which is the exact opposite of the Queen's own power, and she knows exactly what alignment-changing magic can do to someone, and wants nothing to do with it, unless she absolutely has no choice, when the last or penultimate fragment is assembled.
The form of madness is extremely cool, but that sentence makes no sense, either in english or in D&D. Does it affect attacks or spells? To what die does the -2 apply? It would be more streamlined to just have it apply to Diplomacy, Gather Information, Handle Animal, Intimidation and Sense Motive skill checks.
*one step towards chaotic on the law-chaos axis, or towards evil on the good-evil axis if the creature is already chaotic*