Hardware-only temperature-based fan controller?

I have a bit of a weird case... it's a virtual pinball cabinet. It's basically a pinball cabinet with a TV on top (under glass) instead of a pinball playfield. Also inside is a PC and some wiring for pinball controls. The TV gets very hot, so I've got five of these 120mm case fans inside:

http://www.amazon.com/Cooler-Master-SickleFlow-120-Radiators/dp/B0026ZPFDE?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

and they keep the cabinet nice and cool. Only problem is they're pretty loud.

I COULD get a simple fan controller and dial the speed down, but the room with my virtual pinball cab also has eight other (real) pinball tables, and the room gets pretty warm when all the tables are going and there are people playing them all. So I'd have to monkey with the dial a lot if I controlled it manually, or risk heat death on the TV. And the TV is annoying to replace because I need an exact size.

Here's my question: is there a fan controller I could buy to control all these fans and adjust fan speed to maintain a specified internal ambient temperature?

I'd prefer a hardware-only solution where I could place a sensor away from the motherboard, because the TV generates much more heat than the PC.

The form factor isn't important to me; there's a ton of space inside the cabinet. Also, the controller won't be visible, so appearance isn't important.