I just ran across this, Stewart-Warner (SW) has just recently announced their new 5" diameter speedometer and tachometer. For those of you who are building replicas of some of the early racing Cobras, many pictures from the era show a much larger tachometer than the 3.5" or 100mm model.
You can see these new tachs and speedo here...
http://www.stewartwarner.com/Products/feat1.html