From my Archives I can tell you that they were made in Elkhart IN. The earliest ad/photo I have in my files is from 1936 (with canvas roofs!)
Not sure if they were made any earlier!
There is also mention of a tent trailer being made called the Prairie Schonner in the mid 1920's, Not sure if it is the same as I can not find any more info than this:
Try this website Also! http://www.allmanufacturedhomes.com/html/vintage_mobile_homes.htm
There is even a 1954 there!!!
Does yours have the front porch option that unfolded over the tounge? That is what they are most known for!!! Also if you would like more info just email: email@example.com