Funny, when I first saw this thread I thought, geez, didn't that Fizzaly just build a bike?

Now I see you are upgrading and improving. Some of that stuff is probably better replaced than waiting for it to fail. As for the saddle, I just got a Brooks B17 for my bike (broke it in a week commuting and then took it on an 8-day tour). It's great.

Good luck with your upgrades. Of course, we expect to see pictures when it's done.