We have certainly considered it. But it's a tricky proposition. It has to have some sort of dynamic storage, otherwise it's completley unconfigurable. Basically, it would be a small enclosure, with a mini-ITX MB, and a solid state drive, running Embedded XP probably.
But we've stopped even building our own regular hardware box, giving that business to 2partsfusion.com, because we just don't find selling hardware to be a viable business for us at this time. It takes more time than any money we'd ever make off of it. And everyone wants something slightly different, so we just find it better to allow hardware people to do hardware, and we will stick to software, least for now.
Of course, if we find ourselves a couple years from now with the resources and facilities to do it, we would look at this again. But, probably only if we have the resources to have something custom built for us, and are able to move enough of them to make such a thing a viable proposition.
You can always put together something of this sort yourself. It's all basically off the shelf stuff.