Home built vs Mass produced question

[Optimistic Paranoid]

This is a good question to which I'm interested in hearing everybody's answers. RoTXP brings up a good point about window mount A/C's. 
 From what I've seen, a good homebuilt by somebody that knows what they're doing is far better than the average factory built TT. With RV roof air conditioners weighing in the neighborhood of 100 lbs, you would want to insure the roof was beefed up enough to handle it, but sounds like a good way to go.

With the better cargo trailer companies, if they know you are going to mount a rooftop air conditioner, they can put double roof supports on either side of it to handle the weight.  Of course, this means ordering a trailer and specifying that option, as opposed to simply buying one off the lot.

(and if they DON"T offer an option like that, you are better off buying another brand . . .)