HELLO CARLOS! Thank you for taking a moment to look at this.

The setup really isn't complex or unusual, and I'm surprised no one seems to have made a control system that is flexible enough. There are thousands of players that are trying to do this.

What I'm trying to work with now is Emagic Unitor8MKII and AMT8 midi interfaces connected as suggested in the manual : http://www.synthdog.com/Diagram/Unitor%208%20en.pdf on page 20.
 
 
Below is 'Unitor Control8', a utility that comes with these midi interfaces. In this screenshot, I have it configured to receive data on input port 8 and to send the data out of every (all 32) midi out ports. Using this, I can play the keyboard connected to in port 8 with 10 fingers as quickly as possible and there is almost no latency!
Using this however, you can't intercept and alter midi data, and you can only connect input ports 1 thru 8 to the out ports.
There are a LOT of things that I and others would like to intercept and alter.
 

The screenshot below is Hermann Seib's 'MidiTrix' . http://www.hermannseib.com/english/miditrix.htm

It allows connection of any in ports to any outports. This pic shows in port 8 connected to Unitor Out 0(ALL). When set this way, there is almost no latency.
However, when you select not ALL as the out port, but individual out ports as below, the latency is very bad. I don't have the source code for this utility but I emailed Hermann and he was the person who suggested that perhaps a separate thread for each out port would overcome the latency problem.

I also tried the 'Maximum Midi Toolkit', a DLL-based older C++ endeavor. http://www.maxmidi.com/

Using it, the results of instantiating 32 midi out ports, like I tried with DirectMidi and MidiStation, are bad delays when sending data to many out ports. Unlike my altered version of MidiStation however, the interfaces show output on as many ports as data is sent to. MidiStation stops at 16 out ports.
 

As another example that it must be possible, besides setting a midi input to be routed to port 0(ALL) without latency, if you use the giant,
sophisticated Logic sequencer (seen below) http://www.apple.com/logicstudio/ there are no problems connecting a midi input to as many out ports as you want.
Using it to play live is bad though, it wasn't built to be a live performance controller, it isn't intended for
split second switching between midi configurations in a live performance situation.

The Emagic midi interfaces were built by the company that originally developed Logic, later sold to Apple.
Apple just released Mainstage http://www.apple.com/logicstudio/mainstage/ which is a very good idea of what I'm looking for,
but Mainstage only works with Apple VST software, and doesn't even allow integration with Apple's own Logic sequencer!
 

When MidiStation is set with midi coming in and the out port set to port 0(ALL) there is no latency. When it (the altered version with 32 instances of COutport) is hard-coded to send midi to more than 16 out ports, only 16 midi interface out port lights illuminate, and there is a lot of latency.

MidiStation controls (or overcomes upon reception of the next midi event) stuck notes to a greater extent than MidiTrix or the Maximum Midi Toolkit when it gets overloaded with requests to direct data to many out ports. I'm hoping that the more modern DirectMidi C++ approach can produce faster, more reliable results than 16 bit DLLs (which used thunking).
 
 
The system I had been using recently is three networked Opcode Studio 5LX fifteen in/out port midi units.

They run software called 'OMS' and 'Studio Patches' (see below). It is amazing, but is prone to crashing.

The source code is not available, and they are discontinued and unsupported.
The pic below is wiring for just 1 of those Opcode units and a patchbay.

The white unit on the bottom is a rackmounted Atari ST computer!

I wrote some midi control software in C for it in 1986. It accomplished all I needed to do at the time.

The Atari had only 1 midi out port however, and after I started using more than 8 sound modules, it slowed down badly.

As you can see, I've been working at this for a long time. Other hardware I've tried includes the Yamaha MEP4, MidiTemp, Axxess Mapper, JL Cooper Midi Link and MSB16/20, Lake Butler Midi Midigator and others.

Any help would be greatly appreciated!

John