Just getting started on my conversion and I noticed my roof hatches are leaking bad. I was thinking of removing them and making adapters to put the a/c units in there place. I haven't seen anyone do this. My question Is there a reason not to do this.

Lots of folks do that, actually everyone that uses rv type ac units do

you will need to use wood or metal to reinforce edges

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I have looked for a while and can not find an example of this. Would love to see how others have done it.

Try searching using Google. Look for roof air conditioning/Skoolie and you will find as I did, many examples. Hope this helps.