I think $129 is really cheap and worth the risk... They must be wrong about the 31. Look at it this way, if the wheel diameter is 27+1/4, it looks in the picture like the seat tube ends about 4 inches higher. So they must mean that from the floor to the top of the *seat tube* is 31 inches. If there *was* a top tube, it would theoretically be 31 inches off the ground or so. So, that must be what they mean.

Again, just consider the wheel diameter and look at the picture. I don't think it's too big...