Hey guys,
1st post here
I wanted to know about this too. I started receiving some of the hardware for my build.
I can say that the EK-CoolStream Classic SE 240 seems to me that it fits just fine with the front I/O still in place.
Pushed all the way back, with just 6 screws secured into the the bottom rails, the front cables can be bent out of the way without much stress.
Honestly when I "dropped it in" I was surprised it was so easy.
Maybe there's something I'm not anticipating. Placed as far back as it goes, the io plates don't seem to interfere with the fans, but it'll probably shorten the allowable length for the GPU (approx 255mm).
EK-CoolStream Classic SE 240
Dimensions: 273 x 120 x 27mm (L x W x H)
I know it's not the thinnest out there and the fans might struggle for air a little bit, but this isn't really the rad I'm on counting for the most of cooling.