Well, I spoke with Chip at Overclock-watercool today. Told him about the interest in a version of the block that can use 1/2" hose. Came away knowing a bit more on how the block works.
It's not that it flows alot of water, it's the velocity of that water. Turns out the hose barbs on it are 1/8 NPT.. What's going on is the water is being forced through a small passage. This is better than a big passage because more of the water that's going through the block actually touches the block. And with it "blasting" through there, the water around the edges can't sit around while only the water in the center flows.
I bounced a couple bad ideas off him before I landed on the idea he's already working on. Don't want to give away any trade secrets, but it will use 1/2" hose, and should flow more water, and while he won't admit it'll perform better, it won't perform any worse.
Sound cool?
I'm hoping to get one when he's done making 'em and verifying they work.