Well, building from scratch is a good idea because it forces the builder to become familiarized with bikes, so when the bike messes up, they can fix it themselves. It's a fantastic learning experience and since you have access to tools and your friends dad will probably be able to help you out a bit, I say go for it. It'll probably cost a bit more than buying complete, but you'll end up with what will probably be a little better than buying a kilo tt and you'll have the experience.

Now, the more important part is what type of riding will you be doing? What type of frame material are you looking for? What is your budget? etc.

Aside from all of that, if I were in your shoes I'd be interested in building up one of the Wabi frames.