Gaze upon the wonders of the Stealth Tubing CPU water block, designed and built by custom PC builder ModdingCafe, the design makes it so you can hide your custom water loop tubing behind your motherboard. It even works with your standard mobo, so there's no need to buy an entirely new one just for the privilege.
Though, fair warning, there is a little tinkering involved.
ModdingCafe designed this stealthy approach to water cooling with two things in mind—ease of use, and minimal aesthetic. And it looks like it's hit those marks rather elegantly, or so it seems watching the first person to get their hands on the prototype, Der8auer, as he fits the block (via WCCF Tech).
Rather than forcing you to display your tubing around the front and have it get in the way of all your other fancy components, this water block uses four thin tubes that you simply slip through the mounting holes to reroute the liquid through the back of your motherboard.
To get to that point, you do have to remove the CPU mounting latch and replace it with the included custom one, before sandwiching your CPU between the two gorgeous acrylic blocks on either side.
While you don't necessarily need to get yourself a new motherboard, you are going to need to check the spacing for your particular motherboard for this one. As Der8auer realised half way through... their M.2 cooling block was in the way when they tried to pop the custom block in for the first time.
So yeah, just something to keep in mind.
You'll also want to find a PC case with enough clearance around the back to allow you to hide your water tubes as well as the inevitable mass of power and connectivity cabling. And then of course a transparent panel to show your work on the back side, as long as you don't get complacent with your stealthy pipes.
Right now the Stealth Tubing CPU water block is still in its conceptual stages, so it could well change between now and its final form. Still, it looks like a pretty well thought out design and I'm now kinda flabbergasted that it's not already a thing.
In a similar vein, we've seen Asus popping in with cable-free RTX 4070 that feeds the cables through the back of the motherboard. Combine the two and you've got yourself a really snazzy minimal build. Who knows the kind of price you'll be looking at for the lot, though, as for the latter you do need a special motherboard.
Oh, the things we do for a clean system build. Maybe we should just ditch the glass side panels altogether and hide everything away again?