CUPS 1.6 (and the next 1.5.x) will support "Bonjour" discovery using Avahi on Linux and other platforms (in addition to mDNSResponder, which is also open source and works just dandy on the same platforms...)

The problem with CUPS Browsing is that it relies on UDP Broadcasts, which are bad for Wi-Fi bandwidth and power consumption. CUPS Browsing also has issues with hostnames - how do you setup a network using CUPS Browsing without broadcasting IP addresses (printer@11.22.33.44?? Yeck), setting up a DNS server, or syncing /etc/hosts files? All of those things are solved by Bonjour (mDNS, Zeroconf, DNS-SD)

The 5-computer limit does not apply to applications, only to music and video content. You can even re-download apps later as needed (same as iOS).

FLTK (www.fltk.org) is still in active development and is my cross-platform toolkit of choice - C++-based, easy to use, and works on Windows, Linux, and Mac OS X with ports for other platforms available.

OK, so lets put a metal shipping container (i.e. a big metal box) out in the desert and have people sit in there throughout the day - won't that get awfully hot?!?

Roundabouts are not a great thing to have with snow and ice - doing a sequence of tight turns can easily result in loss of control and an accident, not to mention that they suck when you have a lot of traffic.

Yeah, since the roads will be glass they'll replace the plows with big squeegees.

You make it a co-op that is owned by the customers...