A few screenshots, details, links.
Protected mode, 32-bit OS for i486 CPUs and up, full network stack, supports several filesystems, paging, deferred procedure call support, and virtual multiple screens with different resolution and scrollback. Free download.
Open-source, full featured graphical (GUI) 32-bit operating system for x86 386+ architecture; network and Sound Blaster support, mice, video, and many file systems. Website shows requirements, screenshots, status, downloads, documentation, contacts, members, forum, mail list.
Multi-process/threaded protected mode OS for all i386+ systems, written in all 16-/32-bit Assembly in TASM, fully PROMable so can port to embedded systems with no keyboard and/or screen, stable and secure via segment protection and paging. [Open Source, GPL]
Assembly language OS for Intel/AMD x86 architecture made specifically for serving the Web, written originally for the programmer's personal interest and education after moving to the PC platform from his old 8-bit machine. Philosophically similar to V2 OS.
VISual OPerating SYStem: small, fast, home-brewed, open source OS kernel for x86. Includes project background, screenshots, source code and useful links for OS developers. [Open Source, GPL]
By LadSoft; developed years ago and improved since then; planed for redesign to make a viable OS; updates soon. Extant version is good sample of programming standard PC hardware (no PCI) and managing x86 pmode resources. [Copyrighted Freeware]
Multitasking, multiuser business OS; small (100K), integrated file system, low maintenance. Main purpose: fast business online transaction processing. Usually used in vertical markets such as transportation. Not a (unrelated to) DOS variant. By Bluebird Systems.
Runs on i386+, 16-bit real mode, FAT12/16/32 (read-only, LFN support), coded in C++; downloads: binaries, source, utilities, game (tetris source); downloads. [Open Source]
32-bit multitasking, multithreaded OS for x86 386+ CPUs, with GUI, FSs, applications, drivers, all in active development. Site has information, news, documents, screenshots, downloadable releases.