I just spec'ed out a build that I'm going to start once my G.W.Bush check comes in, using one of the Bike Island frames. My total is shaping up to be around 540, and that's lower than yours would be (I have lots of parts in my parts bin, and can get some stuff pretty cheap).
As much as I hate to say it (because I advocate using existing materials instead of buying new, which causes more items to be manufactured, which has all sorts of implications... this will be my first "new" bike ever, and I'm still torn), your best bet (economically speaking) is probably to get that Pista. Plus, you'll have the instant gratification of getting a rideable bike as soon as you pay for it. Learn about it as you go; replace/upgrade parts as they wear out.