There's some good notes on what these can do a retro gaming consoles, including DOS, here:You're probably right. (Partially) Answering my own question; I installed XP SP3 on my Wyse using WinSetupFromUSB, which worked surprisingly smoothly — I had not tried this before, it's been years since I did anything with Windows, let alone XP. I got missing drivers to install using SDIO, all except one; graphics. As it turns out, drivers for the Radeon R5E were never made available for Windows XP, only (seemingly) Windows 7 and onward. I did try a bit of .inf modification shenanigans to see if I could get something working, but I did not get that lucky. I was able to get a driver to install but it would fail to start, with Windows listing it with one of those yellow exclamation points and saying something went wrong with it and the driver couldn't load.
That's as far as I got. It's a bit of a shame, as it otherwise was a very smoth process with sound and ethernet and everything working with just a few drivers needed. I wonder if someone more knowledgeable would be able to figure this out more easily, sadly I'm not all too familiar with this and a quick search seems to show that no-one else tried or succeeded to get later AMD drivers (as in, anything after Catalyst v14, the last one released for XP) backported.
I didn't realize what series these are--a couple of generations ago these do have a native xp embedded dom (embedded standard 2009, as it was a option on mine), so xp should install great:
Wyse Z90D7 Thin Client
Hardware description of the Wyse Z50 (Z50S,Z50D) and Wyse Z90 (Z90SW, Z90DW, Z90S7, Z90D7, Z90DER7 ) thin client hardware
www.parkytowers.me.uk
But for any retro computing, the even earlier era thin clients were really great for this, and they're readily available fully set up and ready to go at reasonable prices like this one:
Wyse V90LE - Windows 98/XP Retro Gaming PC -16GB SSD, 1GB Ram, 1.2GHZ VIA C7 Vx0 | eBay
WYSE Vx0 Retro Gaming PC demonstration - YouTube. -Second partition (7.5 GB) - Windows XP Pro. -NOTE that when booted to Windows 98, you cannot see the Windows XP partition as it is NTFS. -Latest version of Firefox supported by XP.
www.ebay.com