Does casting a spell from a scroll count as you casting the spell for effects such as Spell Focus and other abilities that improve the spells you cast?
If scrolls don't, are there items that do?
The FAQ on this states:
Items as Spells: Does using a potion, scroll, staff, or wand count as "casting a spell" for purposes of feats and special abilities like Augment Summoning, Spell Focus, an evoker's ability to do extra damage with evocation spells, bloodline abilities, and so on?
No. Unless they specifically state otherwise, feats and abilities that modify spells you cast only affect actual spellcasting, not using magic items that emulate spellcasting or work like spellcasting.
Therefore using items to cast a spell never counts as you casting the spell for things that improve spells you cast.
As stated in this FAQ, when using magic items, such as scrolls, wands, or magic rings and necklaces (and pretty much all magic items), you do not count as having cast the spell yourself, you merely activated the magic item, which in turn, cast the spell, using the caster level set in the item. So, if you activate a Scroll of Fireball that was created at caster level 5th, it will do 5d6 damage, even if you are a 1st level caster or a 20th level caster (or not even a caster, for UMD).
However, depending on the context, it might work for what you want, or not. For instance, using a scroll counts as having met the requirement to create a magic item without having to increase the DC by 5, even if you are not effectively casting the spell yourself. It does not count for feats or prestige classes requirements such as "must be able to cast Daylight" (example).
A 10th level wizard with the Scrollmaster archetype can use her ability score, feats and caster level when activating a scroll.
The Panoply Savant occultist archetype also allows you to use your own caster level for magic items that match your implement type (such as wands), starting at 8th level. But no other ability or feat is mentioned, so the caster level of the magic effect is all that is affected. The Arcane Savant prestige class does the same for scrolls.
But, in general, magic items do not gain any benefit from your own abilities unless specifically said so in that item's description, or it says you are the one casting the spell, such as Mnemonic Vestment.
Staves are the only exception to this, as stated under Using Staves:
Using Staves: Staves use the wielder’s ability score and relevant feats to set the DC for saves against their spells. Unlike with other sorts of magic items, the wielder can use his caster level when activating the power of the staff if it’s higher than the caster level of the staff. This means that staves are far more potent in the hands of a powerful spellcaster. Because they use the wielder’s ability score to set the save DC for the spells, spells from a staff are often harder to resist than those from other magic items, which use the minimum ability score required to cast the spell. Not only are aspects of the spell dependent on caster level (range, duration, and so on) potentially higher, but spells from a staff are also harder to dispel and have a better chance of overcoming spell resistance.
This includes spells from the appropriate magic school of your Spell Focus feat.