I had a similar problem, while I had the motivation, I wasn't sure that I'd know enough to put the bike together myself. So I took the frame to the LBS after thinking about it and have to say that I regret it. Some things didn't turn out as I would have liked and I think I might have seen the problems had I built it up myself. And it cost me a fortune. So if I had a second chance to put the Soma together, I'd do it myself.

If you really don't want to try it, maybe you could find someone - not a bike shop, I'm thinking of a friend or someone who repairs bikes privately or just knows enough about bikes - who would put the parts together for you without charging a fortune. If a friend would ask me to do this, it would be a fun project for me, I'd be in for a dinner or something like that.