Maybe "might could" sounds odd or ignorant to most English-speaking readers. A lot of people wrote to tell me that it does. Yes, we say that where I live, odd and ignorant alike. If I had written, "I thought you might be able to get coffee," I don't think anyone would have remarked upon it. I would point out that the meaning practically is the same. However, the dialog was a slip on my part, as I would not have written it that way had I taken time to be a little more careful.
 
 

 
"Click on the cartoon"