Hi, I'm the Classilla maintainer. I noticed this thread and decided to come by to answer some of the questions in the thread.
First off, I noticed that the 68kmla forum default theme didn't work ... the day of release 8-o so alas that was a little late to fix. The good news is that this particular layout failure may be related one I had been tracking for awhile and unable to find a fix for, and the default theme's case is a bit simpler, so this may be a good thing. I am looking at it for 9.0.4.
With regard to the memory usage, having dug into the code, in my opinion WaMCoM was way too optimistic about how much memory it actually required. Moreover, Mozilla code is notorious for memory leaks (just look at your typical Firefox build, even on OS X, and more so on Windows) and this runtime is no exception even though it is simpler and smaller. For that reason, increasing the minimum actually greatly improves its stability; it does not handle low memory situations well. The 80MB is designed to be a take-it-if-it-can-get it phenomenon and you can cut it down to its minimum, but I would not put it below the stated minimum or you'll regret it. It really is a lot happier in 48MB than the 26ish Kai tried to squeeze it into.
There was also the question about the 1400, and I made sure to test it on mine (a 1400cs/117 upgraded to a 1400c/+G3-333 with 60MB physical RAM and virtual memory to 64MB). It runs. It takes up everything the system has, but it does run! And it's not as bad as I feared it would be even though it is no speed demon. I also test Classilla on a G3 blueberry iBook (300MHz, 576MB RAM), a TiBook G4 (867MHz, 1GB RAM) and of course on the build machine, a 1.25GHz MDD dual G4 (1.5GB RAM in OS 9, 2GB total).
For 9.0.4, JavaScript is the primary target. I have some ideas about how to backport a later SpiderMonkey, although Tamarin is probably going to require an extensive rewrite and I'm just not ready for that right now. But if we can at least clear 1.8 (Firefox 1.5), I think you will find a lot of sites suddenly start working. I want to get 9.0.4 out by Q4 2009 if I can.
Again, I repeat my plea particularly for distillers -- people to find bad sites, turn them into test cases and (hopefully) comb Bugzilla for fixes. The more people we have looking at it, the faster we can backport. I did a lot of digging in Bugzilla for this release, which comes after a month and a half of hard work, but there is still a long way to go.
Thanks, everyone, for your kind words.