Build it yourself. A new Supersix Hi-mod frame for $1400(used for about $1100), $1000 a set of carbon wheels, $1400 for Red. You'd be into it for about $4400 and be in the mid 14lb range depending on wheels and bars, stem, seat choice. You would need to do some searching, but I like finding deals.
I actually am in the process of doing just this and I'm hoping for around 14lbs, possibly under, and have about $3000 out of pocket into it. I've been buying, selling and trading for the past year. Started with an 18lb Synapse Carbon 5.