Yeah it's hard to justify builds with that many power slots since you can also use utilities to more efficiently boost your existing power supply (once you have 2-3 power sources) and you get the, you know, attachments
Even if you want to run shields, or presumably high-cost cooling, technically utilities can help there by giving you large energy reserves that'll last through combat. So... design-wise it's hard to require lots of power slots
(it's mainly a question of 1~3; I don't think we need to really design for making 4+ seriously feasible)
More to your original idea, I'm not sure we really have room for more cooling, if only because these additional parts would take up an even larger percentage of the utilities out there than they already do. Unless there's not a whole line of them, but just like one or two, perhaps rare, even.
More on the strategic side of things, I'm not sure if this really adds much compared to the Coolant Injectors we have, since they can already quite effectively deal with very high heat scenarios at little cost.
Anyway, if anything it's certainly an idea to add to the list of potential rare/unique items!
Question: Would anyone else use something like this?