[Question about the new Core P5.]

there are mounts for ITX, you would just have more room for activities!

[Core P5 and AIO cooler]

I have the corsair h100i, and I used it for my CPU. caveat to that, tubing is about 300mm, and it would not go all the way across, I have mine perpendicular to the vents. however!... there is stupid crazy open space everywhere. if you can't reach those vents, pop the rad on its side and you have limitless airflow options

[Core P5 Issue]

there is far too much open space to say it doesn't support an optical drive. it may not have a bracket for it, but that is easy to overcome. I have mine sitting flat, and used the pedestal shown for a water reservoir to mount a blue ray player. used a couple of the covers I removed for the back of the expansion slots to support the other side. ultimately, I will pull the 5.25" cage from my old case and mount it inside this one. there I'd ample room to okay with, especially if you mount your drives behind the mobo. since I'm running 3 SSD and no HDD, heat isn't an issue, so they're safely out of the way. as long s you aren't running 480mm radiator, there are several options to mount 1 or more drives along that front face.

 

hope this helps