It would depend on his idea of light. An average weight of a high end lugged steel vintage racing frame/fork with a ready to ride, but minimal build (no seat bag, pump, cheap tubes, or boat anchor wheels) is around 20-21 pounds. High nineteens, if the build used some of the lighter parts of the day or the frame was lighter than most. The same frameset built with current high end parts would be around the low 19's. With top of the line, but not necessarily weight weenie parts, (SR11, Deda/3T cockpit/post, higher end wheels), you would likely be in the mid 18's. To get a 17 pound bike you would want good full CF threadless fork, and would have done well to use a light frame to start with. Any lower than 17 pounds (and likely well before that point) and you would have to be seriously counting your grams. That's not cheap.

In contrast, there are few models of CF frame available right now that you could build up the high 14's with fairly common, middle of the road parts, and no serious weight weenie garb, for less than It will cost you to build the high end 18 pound steelie. That's a big difference, especially in cost.