Now this subject I know, having worked for the company the designed the electric cooling fan for the Taurus and many other cars.
Most modern fans are custom designed for the resistance of the radiator they come on. You can expect that they will work well on a radiator with similar resistance but a puller won't work well if installed in a pusher arrangement. It'll just stall and not move much air. And you can't spin the fans backward, you might get some air, but you'll be wasting a lot of power. Besides, the motor brushes are off-set on the armature on many motors and will wear out really fast.
There are a lot of after-market pusher and a few OEM pusher booster fans. If memory serves they were an option on some Jeeps and several BMWs and Mercedes had pushers.
However, the sweetest setup is going to be something like what we did on the mid 90's EN-114 platform (Town Car, Grand Marquis, Crown Vic).
Between the engine driven fan and the radiator there is an electric fan that spins in the opposite direction from the engine driven fan. It not only adds it power to the engine fan but because of the reverse rotation air enters the engine driven fan at a more advantageous angle making IT more efficient as well.
This fan come in it's own ring shroud and should be easy to adapt to another application.
Wow, google found me a picture:
The radiator side is facing you.
Jake.