Thought I would upate my progress on this build for those interrested. Will also post a picture of the finished result in the Trek 520 thread when the time comes.

I just pulled the trigger on the frame at the LBS, they will place a special order on monday and should have it by the end of the week, so it's actually happening now!

Wheel stuff arrived yesterday, so i've been busy building, and so far the front wheel has come out pretty good while the rear is still in progress in the truning stand. I ended up ordering the Panaracer Pasela 700x38c in stead of 35c as planned, since the 35 was out of stock. After mounting the 38c on the 19mm internal diamter TK 540 rims the tire measured 34,5mm, and after sitting with 50 psi over night, it had stretched to 35,1 mm this morning. The tire sidewalls are surprisingly thin, while the tread seem more sturdy. I wont be riding any gnarly roads, so it will be interresting to see how the sidewalls will wear.

The build spec is still as in the first post, except from the rear derailer where I will be getting the 4700 Tiagra, based on excelent advise given in this thread.