Level 10-12 really isn't that difficult. A Weirdstone to block teleporation and the like, a Greater Shadesteel Golem with Rudimentary Intelligence, Permanent Emanation (Temporal Repair) and Permanent Emanation (AMF) (have it cast the spells from scrolls with it's UMD) could easily capture a level 10-12 wizard.

To imprison him, knock the wizard out (so that he can't make saves any longer), whack him with a Temporal Stasis spell, and drop him into a permanent Prismatic Sphere with a Permanent private sanctum inside of it that is in deep intergalactic space.

Sure, he can still be Wished back to his buddies but there is nothing you can do to prevent that.