Plane Sailing said:And of course, the basic scry spell takes what - an hour to cast?
Indeed it does. Note since Crystal Balls just let you use the Scry spell, and devices take the same time to activate as the analogous spell unless otherwise specified, it takes an hour of gazing into a crystal abll to use it, and it only lasts a few minutes per use.
However, by 15th level, Greater Scrying is available. Even then, though, there's nothing in any of the Scrying spells that says that anyone but the caster can see what the sensor sees, so no telling 3.0 Summoned Monsters to go teleport to and get the guy "in the mirror". (In 3.5 summoned monsters can't teleport, so the issue doesn't come up).