I'm using the 4.5L to do the same thing. I think that the coolant lines running through the freezer divider is kind of a convenience because all i need to do is unbolt it and move it out of the way. As far as I can tell the "hot" lines are on the sides of the fridge, although I'm still trying to locate a blue print for the thing so I don't have to hold my breath while I drill the holes.
I'm also going to be integrating a 5L mini-keg system I build previously into the back along with 2 pin locks for a total of 3 brews on tap.
I'll fallow the laws of man if they make perfect sense, if not I'm on my own.
Bottled/Kegged: Summer Saison, Simple Sweet Mead, Lemon hefeweizen, Blood Orange hefeweizen
Future: Max's (hopefully) improved IBA, coffee stout