ive seen some passive radiators setups on the net, but they involve huge radiators, like out of a cadillac, custom waterblocks, huge plumbing, and use only moderately hot components. for decent results you really have to place the rad at least 2.5 feet above the block. some also put the rad outside the house, or in the garage. -not exactly AIO.
Oh you're so wrong.
I have two Watercool mo-ra 2 external radiators, without fans.
I get insane temps compared to any active water or air cooling, it can handle well over 500w.
Yes the radiators are big, but they sit under my bed on legs I made in about 5 minutes, so they don't take up important space.
With quick disconnect fittings it's not impractical at all, NO you do not need custom waterblocks (why would you?) and no, plumbing is not huge, it's actually 2,3m long in my case, and it is VERY simple.
It's not even expensive if you buy used car radiators.
If you want ultimate performance and silence watercooling is the only way, and by watercooling I don't mean some crapy AIO.
If you don't have any personal experience with a setup like this, don't say things like they're facts. I hate that.