Well, I have _so_ many projects going right now, I will eventually get around to another write-up (on building from source) at braindeadprojects.com, but haven't had a chance yet.
Typically setting up a build environment and tweaking things with _anything_ that's built from source takes time... I wouldn't say I "circumvented" anything, I simply unrolled the iso, made a couple quick changes and re-rolled it. In doing so, I was able to have a Coffee Shop Kiosk up in a couple of days, with a second one shortly following that (based on the success of the first).
WebConverger seems to fill a real void, surprisingly there doesn't appear to be many (if any) free Kiosk solutions out there, and many of the previously existing ones are no-longer maintained - so Kai's work is a very worthwhile contribution to the community.
One thing of note, I would argue that the statement "The freely available version of Webconverger offers no persistent customization" isn't _really_ true - and here's why: Webconverger is released as an ISO. The ISO is a binary image, similar to say an RPM of your favorite program. (Both are binary releases). In both instances if you want to change artwork or some minute aspect, you typically will need to delve into the FREELY available source, make your edit and re-compile.
Thanks for pointing out Webconverger 12 has been released (and putting LWN.net on my radar, I've now subscribed to it). And Cheers!