Sorry no i dont know about the billion.
Ask autobarn if they have anything similar and tell them what functions you are looking for in it and they might have it or a similar one....
dont they usually stock davies craig thermo fans and accessories.Why not make it easy for them and go to the davies craig website and have a look through the catolouge and see if they have what you are looking for.
Usually if you type in thermo fans on google/similar you would get a larger variety of brand names.Go from there and see what else they have on offer..
Does the controller have to controll twin thermo fans or a single?
May i suggest that you know what temp you want the car to run at and set the sensor a little lower so it catches it/temp before it gets out of hand.This way when you are driving and the car is getting ample air flow,enough to cool the car,the fan will not be in operation.And when sitting at the maccas drive through the fan will come on.This way it wont overrun the fan.Also a problem is getting a fan big enough to do the job properly....
I hope i could answer some of your question at least and not loose you cause i still dont fully understand what you are getting at.
Heres a site that shows you how & what you need for a thermo fan install and what to do. http://www.autospeed.com/cms/A_2015/article.html