OK, so I work for a local POS company and at one time we used these boxes with XP Embedded for the client side OS.

Well these are actually nice little boxes, they are based on the C3 cpu and of course that means the VIA chipset too with the crappy onboard graphics.

Well, I've already swapped out the small Compact Flash with a 1GB module as they have a nice CF -> IDE adapter and swapped out the single 256MB memory module for a 512MB stick.

I also installed Windows 98-SE and my final thought is to swap out the dual-port serial card with a better graphics card.

Since it's also quite small, form factor wise, it does come with a special PCI riser card for a single PCI card, however, it's not deep enough for me to install my old Voodoo 5-5000 into, the card is to long to fit, haha....

I do have another one however, an old Radeon 7000/7200 with 64MB on it.

But of course I was looking to be able to play some older DOS based Glide Games on it as well

I thought I also had an older VooDoo 3 model which maybe short enough to fit like the Radeon does, but I can't seem to locate it anywhere

Does anybody know some online vendors that still have some new/used parts like this ?!?

Try a search on low profile video cards which should give some possible results. One example would be Directron, who carries such cards. Of course you would have to determine if they will actually fit, based on the specs. of the thin client box.

The other possibility would be mini-itx suppliers.