I have and I bought it at lowes up here in Canada.it works great and dropped the temperature by 20 degrees.i had one also in another trailer I previously owned.i also put ultra coat 1000 roof sealer in the white colour which also helped by keeping the temperature down even more.i bought the roof sealer from lowes.i put one inch foamboard bought from home depot which also helps with temp control and it looks pretty good.heres a pic of the solar fan I used,hope this helps.marc.
A metal skinned trailer can be cut with a sharp bread knife There's not much to them really. Good call with the low louvers. If you end up with too much cell capacity to drive a single fan you could take it a step further and use another fan to draw cooler air in at the louvers which would develop a forced circulation to push the hotter air out the top. harbor freight has a whole bunch of different and cheap solar cell solutions. Keep some screen on the inside of those vents. Hornets love little entry doors for home making.