SCO

Looking for a modern server to run SCO OSR 5.0.7 without VM (native), h/w must have manufacturers warranty.

Requirements would be to accommodate light loads of up to 15 users, app does not take more than 30 - 40 MB of RAM and data stored takes up to 15 - 20 GB, no internet connections needed, all users connected on the intranet LAN.

Your recommendations would be appreciated.

I tested one of these in 2013 with 6.0.0, and it installed with no problems, although the machine was purchased with the intention of installing Windows Server 2012. The only problem is making sure that you get the correct model RAID controller. They have about 8 different RAID controllers, and there is very little literature that equates the marketing name of the RAID controller with the technical specification.
Warranty is next day on site.
If you can upgrade to 6.0.0 there is a wider range of hardware available, and you can expect 3 to 4 times the throughput for the same hardware.

What about 5.0.7?

I didn't try it, but based upon how the installation of 6 went, I assume that 5.0.7 will work. As long as you order one of the supported RAID controllers.