Username or EmailPassword
One, more recently then 1998 Operating systems took very little disk space. The original NT4 took very little disk space, and also only used around 16-32 mb of ram. Lean indeed.
ReactOS ( http://www.reactos.com ) is an attempt to write a windows compatible operating system. It currently consumes less than 50 MB of space when installed. Goals are to keep the system as lean as possible.
In order for the fat to be trimmed from linux, we need to replace X + ALL desktop environments...possibly with some type of kernel windowing architecture. While you may say that's bad, i don't necessarily agree. This is the 21st century folks. Find me someone (outside of a hardcore geek) that doesn't have a graphical desktop. Yeah, console linux has it's uses...that's why you keep things modular. We at 667Studios might be starting just such a project in the near future.
Disclaimer: I am a ROS developer (though i don't do much these days due to time constraints and code burnout)