[A/S] A/C, swamp cooler and/or fan recommendations to replace crank-upvent?

[Wayne <wayne2@xxxxxxxx>]

Two questions:

I am considering replacing my 14"x14" crank up vent with one of the following:

-Duo-Therm Penguin rooftop air
  -is it true that it doesn't require any add'l. holes and that it's 
captured to the roof from inside the 14x14 inch hole? I like the idea 
of not putting more holes in my vintage aluminum if at all possible.

-Some kind of evaporative cooler
  -anyone have specific recommendations for a rooftop unit that would 
mount into a fan hole?

-Some kind of {Fantastic, MaxxAir} Fan just to move the air around... 
stale air in a hot trailer is a kind of a cruel and unusual 
punishment that I'm not up for anymore.


The trailer is approximate 725 cubic feet (16' long x 7' wide x 6.5' high)

I am looking for sources for the best prices on each of them if 
anyone's got leads...

thanks,

wayne