Most people that purchase high end bikes do not care about weight.
Most people that purchase high end bikes would rather be the first owner and have an original warranty.
Most people that purchase high end bikes simply do not need what this bike offers. Why buy a highly tuned version of an old groupset that is fairly obsolete for the price being charged?
Berk Combo? Not worth much unless you have the exact same saddle position, which you probably don't.
Bars and stem are same story. Many people replace all of these items once buying a bike.
Having known people that have tried to sell custom bikes they often have the lowest rate of return. No one is going to pay a premium to buy something customized for another person except in very rare cases.
Yup, part it out. It still won't be a great return, but you're more likely to get rid of (most of it). I saw a berk saddle/post go on ebay, but trying to sell a custom frame w/ a custom saddle/post combo isn't going to work well on a complete bike.