Here's my totally one-sided opinion about something you're planning (the power of the internet..)
Go for it. Making a bike then making yourself actually get on it and ride, holy, that sounds like the essence of bike-touring. The worst that could happen is much the same as the worst that could happen with a bike that has the words Long, Haul, and Trucker on it. A friend in Atlanta made a bamboo bike in one of the week long course. Wow, so nice - and simple (single speed, which on its own makes me wish I had one...), and again, something that he made. I would absolutely, without question ride it anywhere and everywhere. If I had to do over again, I would have considered this before doing the Southern Tier.
Everyone knows this, but i guess few truly practice it - they are no rules to bike touring... Certain things make it easier - like 29 gears versus one, the type of bike, etc - but you still have to ride the bike. What better way to feel 100% connected to the entire experience than manufacturing the bike from scratch.
You won't know unless you try...
I commend your efforts, and hope that you've made the decision already to have a go at this.