the steel Jamis Sputnik is ~16.5# and costs $800 for a complete bike, replete with carbon fibre components

a Bianchi Pista concept can easily be built to 15#, and the frameset is $550

i started a thread a while back asking how much people's rides weighed. most were in the 18-20# range.

perhaps you should concern yourself more with proper fit and ride quality. if you want to save weight, concentrate on the wheels.