The DMG does state that you can put MM into wands. You could make a Wand of Empowered Magic Missile, for example, which would be a 3th level spell wand with a minimum CL of 5. A Widened Grease would be a 4th level spell, CL 7, and the DC would be 10 + 1 (spell level) + 2 (14 caster stat for a 4th level spell) = 13, which is 2 points higher than a 1st level CL 1 non-MM Grease (DC 11). It also costs 28 times as much, which is oppressive.
CL is always (unless you craft it otherwise), minimum for the spell LEVEL for the class that is crafting it, after adjustments for MM.
You could make a Wand of Invisible Fireball, which would be REALLY easy since Invisible Spell is a +0 MM. A Sanctum Fireball, however, would still be a 3rd level spell when made (min CL 5). If it was used inside of the sanctum, it would be effectively a 4th level spell (still CL 5). If it were cast outside of the sanctum, it would be effectively a 2nd level spell (CL 5).
Sanctum Spell is the weird one. The thing to remember is that when the spell goes INTO the item, it is just like it would be in the spell slot of the crafter. When the spell comes OUT of the wand, THEN it is affected by the MM. As far as WHO'S sanctum it would be keyed off of, the creator or the wielder, that isn't stated (I'd wager its the creator's sanctum).
The Rules Compendium errata'd the activation time on Spell Trigger items (ie wands). It is now the casting time of the spell. If the spell is a swift action, the wand is a swift action. If the spell takes 10 minutes to cast, so too do you have to wave the wand for 10 minutes. Thus, if you made a Wand of Quickened Detect Magic, it would have a market value of 21,000g, and be useable as a swift action. Hardly worth it, but a Wand of Gravestrike, especially secured in a Wand Chamber (Dungeonscape) is clutch for any Sneak Attacker in an undead dominated world.
