This came up pre-4e release, and reading the rules, I'm thinking it'll be very easy in 4e. Get a level 5 expert, some magic chalk, and use the Magic Circle ritual. With:

Skill Training (+5 Arcana)
Skill Focus (+3 Arcana)
Eladrin (+2 Arcana)
Aid Anotherx4 (+8 Arcana)
High Intelligence (+5ish Arcana)
Level bonus (+2 Arcana)

It's easy to build a prison for any character up to level 15. Characters up to level 33 might needs a few concentric circles till the NPC rolls a 20. To capture a whole party, place all the Fey PCs in one circle, and all the Natural PCs in another. The expert doesn't even need the Ritual Casting feat if she uses a scroll.