Ok at the office now, so naturally I have access to a PHB... so I took a peek at the rules for delaying as I thought it mentioned something about this...
(page 288 PHB for reference)
Basically, it says that you do not have a normal end of turn when you delay. It goes on to state specifics about each effect type as follows...
End Beneficial Effects when You Delay: At the moment you delay, end effects that last until the end of your turn and that are beneficial to you or your allies.
End Sustained Effects when You Delay: You can’t sustain a power if you delay. At the moment you delay your action, the “check actions spent” part of the end of your turn occurs. Because you haven’t spent an action to sustain any active powers, sustainable effects end.
So with all that said, In your example of blinding barrage (and using the ars ludi system), the enemies could be effected twice (to the benefit of other PC's) but that would be it...
================
EX:
Rogue: Blinding Barrage
PC2: attacks (vs blinded target)
PC3: attacks (vs blinded target)
PC4: attacks (vs blinded target)
PC4: attacks (vs blinded target)
Enemy(ies) goes
PC2: attacks (vs blinded target, again)
PC3: attacks (vs blinded target, again)
PC4: attacks (vs blinded target, again)
PC4: attacks (vs blinded target, again)
Rogue: attacks (ending blind effect)
=========
In this sequence, the enemy goes next, so in order to drag out the effect any further, the Rogue would have to institute a delayed action (to drag out his turn past the enemies next turn) which would end his effect.
I can understand ruling that they are only blinded one time, but for me that's more involved tracking than necessary and goes against the reasoning for using the ars ludi system in the first place. Allowing it can give the PC's the advantage, but like I said before, I would just make things slightly harder if things were going too easy for them - and though I can't think of any specifics off hand, another thing to consider is that any tactic such as this that the PC's employ, so too can the monsters
