OK, let's start from the basics here...first of all, the Neutron (and anything else that already has a powered case) doesn't belong in the Eurorack cab. Let's assume that we're looking at a typical 2 x 104 case here; I'll use the Tiptop Mantis as an example...
A Behringer Neutron currently streets for $290, and comes in a case with power already. A Mantis streets for $335.
Since a Mantis has 208 hp total in space, now we'll divide 335 by that 208 hp figure...and get 1.61. This is how much each hp in the case costs. Multiply times 80, and you get 128.85 (rounded). This means your Neutron, when in the Mantis, doesn't cost $290...it ACTUALLY costs $418.85, because you're now using expensive Eurorack cab space to house and power something that's already housed and powered. Any time you decase something that's already housed and powered, this happens, and it's necessary to tally up an ACTUAL cost per hp to see what an action like that really costs! In the end, while it might be convenient to put something like that in with the rest of the modules, it's a spendy solution to something that technically isn't a problem in the first place.
So...before anything else gets decided, you need to sort out whether you MUST have the Neutron in the Eurorack cab, or whether sensible economics is going to prevail here and there's a free 80 hp all of a sudden.