I don't think this has been noticed before. Check out the Iron Sign ability from Nar Demonbinder
. This has never been dealt with in a Nar Demonbinder handbook before.
Iron Sign: On reaching 2nd level, a Nar demonbinder learns how to fashion a special token known as an iron sign. Creating the token requires three days and 1,000 gp in magical materials. The iron sign is the size of a large amulet. The demonbinder can use it in one of two ways.
Calling Diagram: The iron sign functions as a calling diagram (see Conjuration under Schools of Magic in Chapter 10, Magic of the Player's Handbook) that combines a magic circle with dimensional anchor. The demonbinder need only set the token on a suitable surface, and no Spellcraft check is necessary to scribe the diagram. A creature held by the iron sign must remain within 5 feet of it and otherwise behaves as if it were completely enclosed in a suitably sized calling diagram.
The iron sign can hold a called creature for up to one day per caster level of the character who crafted it. Unlike a normal calling diagram, the iron sign cannot be disturbed unless something physically removes the token from the spot where it was placed (naturally, the called creature cannot disturb the token either directly or indirectly).
Demon Trap: As a full-round action, the demonbinder can set the token on a suitable surface and try to compel a free outsider within 30 feet of the token into its effective calling diagram (Will save negates, DC 10 + Nar demonbinder level + Nar demonbinder's Charisma modifier). The subject is entitled to spell resistance. If the creature fails its saving throw, it is transported to a square of its choice within 5 feet of the iron sign, and trapped just as if the demonbinder had conjured it into a calling diagram.
When a trapped creature leaves the iron sign (because it was freed by the demonbinder, escaped on its own, or the duration of the calling diagram lapsed), the token crumbles into powder and is destroyed.
Now Magic Circle against Evil
A magic circle leaves much to be desired as a trap. If the circle of powdered silver laid down in the process of spellcasting is broken, the effect immediately ends. The trapped creature can do nothing that disturbs the circle, directly or indirectly, but other creatures can. If the called creature has spell resistance, it can test the trap once a day. If you fail to overcome its spell resistance, the creature breaks free, destroying the circle. A creature capable of any form of dimensional travel (astral projection, blink, dimension door, etherealness, gate, plane shift, shadow walk, teleport, and similar abilities) can simply leave the circle through that means. You can prevent the creature’s extradimensional escape by casting a dimensional anchor spell on it, but you must cast the spell before the creature acts. If you are successful, the anchor effect lasts as long as the magic circle does. The creature cannot reach across the magic circle, but its ranged attacks (ranged weapons, spells, magical abilities, and the like) can. The creature can attack any target it can reach with its ranged attacks except for the circle itself.
You can add a special diagram (a two-dimensional bounded figure with no gaps along its circumference, augmented with various magical sigils) to make the magic circle more secure. Drawing the diagram by hand takes 10 minutes and requires a DC 20 Spellcraft check. You do not know the result of this check. If the check fails, the diagram is ineffective. You can take 10 when drawing the diagram if you are under no particular time pressure to complete the task. This task also takes 10 full minutes. If time is no factor at all, and you devote 3 hours and 20 minutes to the task, you can take 20.
A successful diagram allows you to cast a dimensional anchor spell on the magic circle during the round before casting any summoning spell. The anchor holds any called creatures in the magic circle for 24 hours per caster level. A creature cannot use its spell resistance against a magic circle prepared with a diagram, and none of its abilities or attacks can cross the diagram. If the creature tries a Charisma check to break free of the trap (see the lesser planar binding spell), the DC increases by 5. The creature is immediately released if anything disturbs the diagram—even a straw laid across it. However, the creature itself cannot disturb the diagram either directly or indirectly, as noted above.
Now here is the incredible part of this ability. The Iron Sign abrogrates the need for the physical circle surrounding the trapped creature - its bound by the Iron Sign. Normally you could cast some spells at the trapped outsider, but its generally accepted that anything that physically crosses the magic cirle breaks the circle, freeing the outsider. From DMDM's Guide to Planar Binding
Debuffing your target. A much-discussed question is whether you can cast debuffs on the target creature in order to make it more amenable to your demands. If you accept the "binding happens/fails as soon as the creature appears" rule, you can't cast debuffs for that first check unless you have some sort of area debuff up and running ten minutes in advance. However, if you fail that first check, can you cast debuffs on the creature for the second check, 24 hours later? Well, there's no question that you can cast one spell -- Agonize, which is specifically designed for the purpose of convincing unruly outsiders to cooperate. Otherwise, though, can you cast Enervation? Dominate? A question to James Jacobs provided the following answer: "You can cast any spell you want at the outsider in the circle, but those that create physical effects that cross the circle would let the monster out. What entails 'breaking the circle' is left to the GM, but you could certainly argue that the beam of black energy from a ray like enervation counts, or even the faint mist produced by mind fog."
FWIW, here's my personal interpretation: spells that involve energy, that do damage, or that create any sort of physical area affect will break the circle. Spells that produce purely mental effects (like Dominate) or that produce effects on the target without a ray or any other connection to the target (like Baleful Polymorph) will not break the circle. If you're planning to go this route, try to get a ruling from your DM first.
The Iron Sign means that you are free to use rays, mists, spectral hand
to deliver touch spells, or even enervation to debuff the trapped outsider. Iron Sign is a 1st tier planar binding ability.