Nice looking fleet of Whites you've got there. I'm going to dissent and say that while I like the single stacks, I'm not a fan of the big stacks; but that's just my opinion (and they're your models). Well done.
There was a guy out of Hamburg, Germany, that made P/E fans for a while. I think his name was Harold Weber, but I don't know whatever happened to him. As far as i know, his fans were the only ones available. Some of the CTM sets might have fans, but I'm not positive. Oh, and they're not just in "old trucks". Our 2002 Smeal Ladder Truck has these fans in it.