I found a '90 Maxima dual fan at the junk yard this weekend. The width is perfect for our radiators but you will have to come up with top and bottom mounts.
I got it installed and working with a Hayden dual fan kit from Orielly's. $18 for the fan and $36 for the controller kit. It has a potentiometer to fine tune the activation temp and I have it wired to come on with the AC.
The butt dyno is very impressed with this one. Out of all the mods I have done over the years to this truck this is the only one I can honestly say freed up some horsepower. The pull in the upper RPMs is definately improved. The fans are much quieter than the mechanical fan. Best of all, the AC actually blows cold with the truck not moving.
Everyone should do this IMO.