Has anyone found these for sale in Chiang Mai or possibly online?  I'd like to see what is available here and what the prices are.  I'd prefer the larger gable vent fans as apposed to a roof mounted one, but right now, I just want to see what is out there and available.

I looked high and low, no chance of anything similar to be found in this neck of the woods (one year ago).

I found this searching 'gable vent fan':

http://www.ebay.com/sch/items/?_nkw=gable+vent+fan&_sacat=&_ex_kw=&_mPrRngCbx=1&_udlo=&_udhi=&_sop=12&_fpos=&_fspt=1&_sadis=&LH_CAds=&rmvSB=true

In our garden house there is 12 volt supply via solar panel. At a car butcher's(?) place I bought old cooling fans for 600 Baht/piece.

They blow really strong; no idea how much power they need.

 

Just to throw it in , they also make them for the side window of your car , 

 

roll down your side window , stick it on the glass and roll it up.....

Something for you to look at;

 

https://www.aliexpress.com/wholesale?catId=0&initiative_id=SB_20170104041420&SearchText=solar+gable+fans