I think I have arrived. This Ensemble OS is what I've been looking for. I've been studying the GEOs developer SDK I got from Breadbox and essentially this OS will support anything you could have imagined writing in 16 bit real mode in C++, which means the sky is the limit in terms of functionality. You can access all the COM and parallel ports directly just like you would do under DOS and the comms protocol supports connections to TCP-IP or IPX (I will likely design everything for IPX from the beginning and see how it goes) seamlessly for any app running on the desktop.
The only problematic program I found in Breadbox that gives you an error is the performance monitor. When running it alongside the screen dump utility or other apps concurrently it appeared to generate a system error. Otherwise, I have been death marching this OS since Sunday, with an automated script (built-in macro editor!!!) loading programs and exiting over and over again to see if it would crash. Nothing there yet. I think it is pretty solid, it would have to be since it is built on 24 years of GEOs technology and drivers. I could winge about the display GDI interface, which is slow under VESA but there may be way to optimize this once I learn more about how it works. The error trapping is far better than under Windows - a critical error prompts you it will exit, after saving the last safe configuration.
Pretty amazing, right? I just sat here for an hour staring at the screen after I got it to come up on the $12.95+shipping 486DX single board computer I bought on EBay. I still can't believe you can view PDFs with this thing and run a fully loaded spreadsheet and an HTML browser in another window. I have no idea how they get this thing to run in 500K with an EMS swap manager. That display is right off the high color VESA chip on the minicomputer. If this OS did nothing but allow you to browse a directory and view PDFs I would have gladly paid twice what I did to get a copy.
P.S. There's an existing app that lets you monitor and tune a radio card connected to this board - AM/FM/SW/DB/UHF - that sits right on the Ensemble desktop. I've been looking at the SDK and there is a uniform way to talk to external interfaces like the new line of radio cards for PC-104 and regular ISA bus cards. There is also an interface to the old X-10 protocol for home automation, which does support 12 volt devices with the right equipment. (http://www.x10.com/) Amazing! I'm scared I will never get to sleep tonight if I keep playing with this SBC so I'm going to put it aside and get some rest. In case you're wondering what I've been babbling about for the past year on Vault-Co, this was basically what I had in mind.
P.P.S. The list of included video drivers is pretty extensive, including legacy displays more than thirty years old. There are drivers for monochrome screens in extremely low resolutions, which means this OS might be able to run displays on the new line of zero energy organic flashram LCDs and the increasingly cheap VFD panels with excellent viewing characteristics in lowlight conditions that come in green, orange and yellow flavors.
P.P.P.S. Huge Help authoring system and E-Book reader included with Ensemble. The help authoring system is also configured for callbacks in the SDK, which is exactly the kind of thing I was thinking about for Vault-OS, where a dynamic expert system greets you when it comes on and prompts you for your situation followed by operating procedures i.e. if this is a possible nuclear emergency, it tells you to unplug all EMP breakpoints, close blast valves, shows you where to check to make sure equipment is secured in anticipation of ground shock, etc. Most important of all, it has built-in sound card support so there are numerous voice synthesis options and voice prompting capabilities.