Dura Ace and Ultegra are road racing components. They're lightweight and not all that durable (you're mostly paying for low weight and fast precise shifting, not durability). They're also not well suited for touring due to the narrow gearing and caliper brakes. If you want to build a serious touring bike, look at Shimano's mountain bike parts, namely the Deore LX and XT. Get a 9 speed cassette with a wide range (11-34 is common) and a mountain or touring triple crankset (22-32-44 or 26-36-48). For shifters, get Tiagra if you like STI or use bar end shifters. XTR, XT, or LX derailleurs. As for the wheels, rather than A319 with 105 hubs, look at A719 rims with XT hubs and 36 spokes. If you want a classic look, a honey brooks B17 saddle with matching bar tape looks rather nice on a black frame with silver components.