Bodices and Bustles
Level: MU 5
Components: V, M
Casting Time: 5seg
Saving Throw: none
Duration: 1 year/lv
Area of effect: 36sq feet+1sq foot/level and see below
Explanation/Description: This spell is cast upon a doorway (ie, a portal with an attached movable door) and creates an extra-dimensional space which is anchored to the door frame. The surface area of the doorway can not exceed the given area of effect, and must be shaped to allow the caster to pass. If the door is opened then whatever was behind it before is still there and can be entered and used as normal.
However, if the door is opened while uttering a command phrase (chosen by the caster) then it will instead lead to the extra-dimensional space. The room has a floorspace equal to the caster's level in feet squared (ie, a 9th level caster can have a 9'x9' room or a 4½' by 18' room). As with the doorway, the space created must allow the caster to enter fully. The ceiling height is that of the top of the door frame.
It is possible to cast two or more instances of this spell such that they overlap in the extra-dimensional space, in which case a single room is created with multiple doors and perhaps, if carefully placed, an increased floor space.
Note that the spell is anchored to the doorframe and if the doorframe is moved without damaging it, then the rooms will too. If the door is damaged then entry to the spare room is blocked until the door is replaced, although those already inside may leave. If the doorframe is broken then the contents of the room are deposited back in the "real world" as a safety precaution.
If the magic of the spell is cancelled (e.g., by dispel magic) the room is cut off and the contents will be trapped there until the spell runs out, at which point the safety mechanism will kick in.
The spell may be made permanent, but may still be dispelled, in which case the normal duration will re-assert itself in respect of the extra-dimensional space.
The material component is a embroidered cloth representation of a house which is turned inside out at completion of the spell and which re-appears when the spell expires.