Given the amount of effort, I'd say around 180.. or 250 if you want me to horribly attempt the enclosure graphic! (although it'd still look better than a Zvex!)
They aren't too tough to build... Though, in my opinion, I prefer the AMZ mosfet boost as a booster and a standard TS-808 as an overdrive rather than the single Klon. I do use Marshall voiced amps though. The Klon does sound decent though a Fender amp, but not $500 decent!
If you guys are interested in get started building up the old stompboxes visit diystompboxes.com, there are other sites too, but start there