My miniature goats have a house made of 2-by-4's that is about 10 foot long. 3 foot wide and 3 foot high. The entire "roof" is hinged for easy clean out and has served well for more than a decade.
However, I also have two 110-gallon water trough "houses." One is turned upside down with a doorway cut into one side; the other is simply tipped on its side and has a piece of laminated plywood hung over half of the opening. Each will accommodate two goats comfortably.
I love miniature goats, but my most troublesome is Tessa, a beautiful blue-eyed Nigerian diva. She has outwitted me on fencing more times than I can count. The least troublesome in terms of escaping have been the fainter crosses who seemed to have no interest in the greener grass on the other side of the fences.