No love for Windows 2000? NT kernel with the classic Windows interface. It ran pretty well on Windows 98 machines and was extremely stable.
Though I think I may have had a proper dos boot disk for some games, hard to remember, it was quite awhile back. :)
But I've tried anyway. Then I got owned so hard by Nimda that it is still the first thing that comes to my mind when I think of Windows 2000.
Fast and light as Windows 98 but more stable than Windows XP.
I don't think so, for example requirements for RAM:
Windows 98: 16 megabytes (MB) of memory (24 MB recommended)
Windows 2000: 64 megabytes (MB) of RAM recommended minimum;