I resisted weighing in on the discussion when it devolved into lug design blogging, but the original talk about head tube extension prompted me to examine some of my own variations. I've never been particularly fond of the look of most of the extended designs, but when it is done well and blends into the overall look of the bike it can win me over. Besides, extensions can take many forms. Looking at an early 80's De Rosa, there is only about 3.5mm of extension on the lug. My Stan Pike with Prugnat lugs has 5mm of extension. The Baylis has 1cm, the Land Shark 1.5cm, and the Weigle 2cm. None of these bikes are set up with the bars level with the saddle. What's interesting is that I have set them all up within a small margin of each other. The Weigle, with it's lower BB and greater extension has the bars are 5.5cm below the top plane of the saddle, the closest saddle/bar measurement of them all. It's interesting how the rest in the comparison fall in. The Pike, a vintage early 80's set up, is 7.5cm. The Land Shark 8cm and the Baylis 8.5cm. My saddle-to-pedal measurement remains constant. This all sort of comes down to aesthetics and the look vs. the fit, but many factors come into play.
I've posted some pix so you can all play along.
http://www.wooljersey.com/
Wayne Bingham
Lovettsville VA (but packing for Singapore)