Ich denke Daeinar liegt in einem Punkt falsch oder ich habe seine Antwort falsch verstanden. Ich denke nicht, dass man sich in dem Concealment von Blur verstecken kann. Das geht nur in einer "area of concealment" nicht in einem auf eine Person gewirkten Zauber.
Um das auch nur nochmal zu klarifizieren:
Ich denke auch nicht, das es gehen sollte, der Wortlaut gibt es nur erst einmal her. Die Beschreibung des Hide Skills allein widerspricht dem aber auch schon. 
Genau, aber manchmal ist nicht der Wortlaut entscheidend sondern der Sinn und Zweck der Regel.
Schaut man sich z.B. die Concealment-Regel an wird deutlich, dass Concealment grundsätzlich einen Bereich(area) umfasst.
CONCEALMENT
To determine whether your target has concealment from your ranged attack, choose a corner of your square. If any line from this corner to any corner of the target’s square passes through a square or border that provides concealment, the target has concealment.
When making a melee attack against an adjacent target, your target has concealment if his space is entirely within an effect that grants concealment. When making a melee attack against a target that isn’t adjacent to you use the rules for determining concealment from ranged attacks.
In addition, some magical effects provide concealment against all attacks, regardless of whether any intervening concealment exists.
Grundsätzlich ist Concealment also auf "squares" bzw. "space" bezogen. Eine Sondervariante ist das magische Concealment. Der Punkt ist, dass Hide sich der internen Spiellogik nach nur auf Concealment in einem Bereich bezieht. Mir ist klar, dass der Wortlaut das so nicht umfasst, aber die FAQ stützt das in der Klarifizierung zu Hide in Plain Sight.
Can a character with Spring Attack who begins her
turn hidden move up to a foe, attack him, then return to a
position of hiding? Is she considered to be hiding (that is,
invisible to the foe) when she makes the attack? What if the
character has the camouflage or hide in plain sight class
features?
Normally, a character can’t make a Hide check right after
attacking a foe, since that foe’s attention is now focused on her
(even if the attacker started her turn hidden or invisible). The
sniping option (on page 76 in the Player’s Handbook) allows a
character to make a move action to hide immediately after
making a ranged attack against a foe at least 10 feet away, but
D&D FAQ v.3.5 16 Update Version: 11/24/05
this doesn’t apply to melee attacks (even those made with
reach). Even if the character has Spring Attack, she simply
can’t make a Hide check while she is being observed.
As far as your second question goes, unless the character’s
approach remains entirely in an area where she can hide (that
is, an area with sufficient cover or concealment to attempt a
Hide check), the character is not considered to be hidden still
when she makes the attack. Conceivably, your character might
begin her turn hidden in overgrowth, move up through the
undergrowth to attack a target, then move back to a hiding
place within the plants, having never left the area of
concealment. In this case, she’d be considered hidden when she
made the attack, although she’d have a –20 penalty on her Hide
check.
The third part of your question changes the situation
entirely. Separately, both the camouflage and hide in plain sight
class features make this tactic more useful, but together, they’re
incredibly effective.
A character with the hide in plain sight class feature
(described on page 48 in the Player’s Handbook) can make a
Hide check even if she’s being observed. This doesn’t require
any extra action to accomplish (unlike the sniping maneuver).
The character could attack a foe, then move to a place with
sufficient cover or concealment to allow a Hide check, making
the Hide check as part of movement. The character doesn’t
need Spring Attack to pull this off, although that feat would
allow her to move (potentially from a place of hiding, although
that’s not necessary), make an attack, and then move again to a
place of hiding. Still, unless the character has cover or
concealment for her approach, she’s not considered to be
hidden when she delivers the attack.
The camouflage class feature (also on page 48 in the
Player’s Handbook) allows the character to make a Hide check
in any sort of natural terrain, even if it doesn’t provide cover or
concealment. This means that the character could begin hidden,
move up to a target across open terrain, and make an attack
while still being considered hidden (although she’d still suffer
the –20 penalty on her Hide check). Even if the character has
Spring Attack and moves away after the attack, she can’t make
a Hide check to hide after the attack.
Put all three of these elements together—such as in the
hands of a high-level sneaky ranger—and here’s what you get:
1. The character begins his turn hidden (as long as he’s in
natural terrain, he doesn’t even need cover or concealment).
2. He moves up to a foe across natural terrain and makes an
attack (making a Hide check with a –20 penalty to be
considered hiding when he attacks).
3. He then moves back from the foe and makes a new Hide
check to disappear from view (again, he doesn’t need cover or
concealment while in natural terrain).
4. The foe then, if still standing, says, “Hey, what hit me?!”
Hier wird das ganz gut deutlich, dass mit "concealment" der Hide-Beschreibung eine "area of concealment" bzw. eine "hiding place" gemeint ist.
Deutlich wird dies übrigens auch durch die Erläuterungen in Song&Silence auf die ja die 3.5E Regelung im Prinzip beruht.
Blur gibt nur demjenigen Concealment der unter Einfluss des Zaubers steht aber nicht auf den Bereich um ihn herum, daher kann man sich nicht verstecken. Genausowenig wie man sich etwa hinter einer Wall of Force verstecken könnte, obwohl die Total Cover gibt.
Was Kilamar mit dem Zauber Chameleon meint verstehe ich auch nicht ganz. Wenn der Zauber aus Complete Arcane gemeint ist, dann gibt dieser ja auch kein Concealment sondern nur einen +10 Hide Bonus. Damit kann man sich aber auch nur dank Cover oder "area" Concealment verstecken.
Gruß Zechi
