Thorn Manacles can be done as a magical block or grapple at the original crafter's Craftsmanship+2, just like Incite Emotion can do blocks at Deceit or Intimidate +2. After all, the manacles work by inciting pain to disrupt concentration, not an actual block that prevents the bound wizard from drawing in magic. Assuming a craftmanship of Superb, they'd provide an Epic (+7) block, more than enough to block Harry Dresden without his Foci. They'd cost -1 refresh as an Item of Power.
A spell-repellent mail confers Physical Immunity to Mortal Magic. That's -3 refresh. Adding a +2 rebate (if the item is obvious) or +1 rebate (if it can be hidden), it comes down to -1 or -2 refresh. That would only block direct attacks though, not maneuvers.
Something like Lord Raith's magic immunity would require a major threshold effect on himself. A Legendary threshold would outright stop the vast majority of magic and cut off thaumaturgy that didn't have a piece of him or his Name for sympathetic link as thresholds are magical borders. That kind of ability would cost -6 to -7 for a Legendary Threshold and would require either Outsider powers or the individual in question to contain lots of Mordite.