Crane, I was saying having the Rad in the front of the CMstacker, remove like 6 of the drive bay should provide enough space.
You can "expose" it or perhaps cover it with fan filters.
It'll get dusty if set the fan to "pull"
i.e.
|............|
/............|
/............|
|...........\#
|...........\#
Back Front,
with / being the exhaust fans, \ being the "sucking" fans and # representing the 120mm rad. Dust can be fixed with weekly vacuuming of the front (if left exposed / filter)
Sorry for bad diagram, thot I'll be more "Visual".
Edit: You can put 3fans, I'm placing bets you can put a 120.2 Rad.