Is there a lower limit on casting spells from scrolls, wands and staves?
For example does a scroll (or staff with or wand*) of cold ice strike requires a standard or a swift action to cast?
(the question naturally extends to spells unsing the quicken metamagic)
*yes i know that wands go only until 4th level but let's disregard that for the moment (since i couldn't find a swift action spell at 4th level and under)
Under Magic Items it says "Activating a magic item is a standard action unless the item description indicates otherwise. However, the casting time of a spell is the time required to activate the same power in an item, regardless of the type of magic item, unless the item description specifically states otherwise."
Potions are a little different as it says "Drinking a potion or using an oil is a standard action. The potion or oil takes effect immediately."
Wands (and staves) say "Wands use the spell trigger activation method, so casting a spell from a wand is usually a standard action that doesn't provoke attacks of opportunity. (If the spell being cast has a longer casting time than 1 action, however, it takes that long to cast the spell from a wand.)"
So, I could see a scroll of Enlarge Person still taking one round to cast. However, a Potion of Enlarge Person can be drunk as a standard action and the effect takes place immediately. A wand of Enlarge Person would also take one round just like a scroll.
If you wanted an item that was a swift or immediate action then I think that you would have to speak with your DM. All of the descriptions are usually standard action or longer, not "or shorter."
That is just my two coppers!
I re-read the rules on scrolls, wands and staves and it seems you are correct, the casting time is standard action+.