I always just used batteries when I had multiple pedals, although I never had more than 2 or 3 at a time. Looks like for the cost of that Flatliner you could buy a lifetime's worth of 9Vs. Do you want to just build the thing yourself? You could always
buy one. Have you thought of getting an all in one unit, like a POD?
On a guitar related note, and at the risk of threadjacking, has anyone ever used flatwounds on an electric? It's time for a setup and a restring on my electric, so I was thinking of trying something different.