eskimo.com in Seattle ran on a Model 16 for several years. It was definitely Microsoft Xenix. My brother wrote the multiuser chat system on there, nice piece of software.
hell, Microsoft's internal mail system was Xenix. The last remnants of Xenix weren't removed from Microsoft until the Tide servers came online - ITG ran a xenix machine as a Usenet spool and telnet proxy until 96 or 97.
