The Firefox codebase definitely has some huge issues, but does anyone remember the big Netscape rewrite for version 6? Joel does. http://www.joelonsoftware.com/articles/fog0000000069.html

I wrote a rather long post on my blog a few months ago on this exact issue. After doing some research, I couldn't really find a language or technology that would meet my needs, but I did come up with a better idea of what I would consider to be an ideal educational program. http://angrymen.org/uncategorized/towards-an-educational-programming-language-for-children/