Bah, I dunno the price on this thing, but here goes:
"Extraplanar Trap Box"
This is a small shoe-sized box that once opened, a rope will spring forth and try to latch on the victim (a touch-attack), if it succeeds the victim drops to the next smaller size category (the victim regains a size category every round not in contact with the rope) and the rope attempts to grapple (considered as a Small creature with 20 Strength), every round in contanct with the rope reduces the victim another size category until it reaches size Tiny or smaller in which case the rope would drag the victim inside the box to an extraplannar space (as with a Rope Trick spell) and the box would shut itself.
The creator may put anything it wants in the extraplannar space (harmfull things if they like

), or just have the rope bind the victim indefinitely.
Its nearly impossible for a trapped creature to escape by itself as it would have to brawl itself away from the rope, and try to escape from the extraplannar space to the "box", and still would have to break it to get out.
If the box were to be destroyed, any trapped victims fall outside as if the Rope Trick spell had ended.
Prerequisites: Craft Wondrous Item, Rope Trick, Animate Rope, Reduce Person
Cost: Duh! I dunno