The height of your bars could change if you get a frame with a different headset angle. but I think most of them are around 72 degrees, so it would not change by much. Edit : I worked it out. just as an example lets say your hub to your bars is 800mm. then on a bike with a 72.5 degree head angle the height would be about 763mm and on a bike with a 71.5 degree angle the height would be 759mm. So in my example measured only from the hub, becouse the wheel is the same on both, changing the head 1 degree changes the height 4mm.