It is a working app, but I wrote it to exercise highchair and to potentially serve as a reference point for some basic best practices in both Unfiltered and highchair (you'll see block-based validation handling there, as I've seen that recur un my UF apps).
Awesome! A while back I made a gae template too . Just catching up on email before I pass out. I'll check out yours later. This  is pretty fancy. I love learning about these algorithms. I tried something like that before for generating short urls for pastebin entries  (thats kind of dated now). Highchair seems like a cool idea, and name :), I had to write some custom scala wrappers around da actually have a little gae project planned that Ill probably use highchair in. Fantastic work!
1 - Dang, I missed that! We should combine them. I want to add highchair once I push artifacts to a public repo, but that might better fit a different template.
2 - That's Tantek's algo, I just ported it (it's a basic num sys conversion though).
I do hope you use highchair - more use == better library. I know of a few things that need tweaking (ie replace reflective ctor resolution with a statically checkable function), nevermind additional features.