Maybe I misread it but doesn't chordz easy mode use the white keys for the main note and the black keys for the chord variation. That sounds similar to the approach you seek ie using two fingers.
 
EDIT: I just tried Chordz and cannot get it to do anything in Easy Mode so scratch that.

It does the same  as midiChords, it's a one finger chorder. I'm looking for a keyswitch approach that requires two fingers.
 
If the keyswitch range was 12 semitones, then instead of assigning one chord to one note, I can assign twelve.
 
I forgot I have Chordz, but when I did a quick search, I recognized the CodeFN42 from my menu.
 
I'm guessing what I'm looking for doesn't exist, but there have been a number created in the past few years, and came close to the idea, so I was being hopeful something had come along

On the subject of one note chorders, this absolutely blow my mind every time I watch and listen. It's ALL being triggered by just one note. Four Chorders in parallel, triggered from the one monophonic controller.

The closest I've seen, which won't give you MIDI, is Strummed Acoustic in Auto Chord mode
 

 
I'll check some of my others ...

Strummed Acoustic acoustic's key switches are strumming patterns I believe, in the similar way as instacord uses key switches, rather than voicings.
 
I'm wondering abut using program change messages assigned to keys, then changing programs in midiChords, but I'm concerned abut not off messages.
 

Kamikaze
 
But I've been wandering abut a different approach, based n a key switch style, and wondered f it already exist.
 
Is there a chrder were in a low octave range 'keyswitch style', you can defince the voicing, (major/minor, Triad, 7th, 9th, inversion open/closed, drop two/four), then use the higher range for defining the root.

Yes, as far as chord types go.  It doesn't do alternate voicings, inversions, etc.  MIDI Chord Player is a built-in MIDI plugin within Waveform, so it appears to be locked to the host DAW.
 

 
Tracktion Waveform MIDI Chord Player

 
There are key switches for 12 chord types, using one octave of the keyboard.  So if you press a note elsewhere, you will play the root note of in whatever chord type you have selected with a keyswitch.
 
You can record your performance to a MIDI track, and then render your generated chords within that track.

If you have the tool that does chording you like, just record the same midi on two tracks and send to two synths. Each synth uses a different pattern. Use a midi event filter to let through the note range appropriate to each chord type. Invert the range on the two tracks so only one ever plays at a time.

That's pretty damn close to what I am looking for and is what I've described, hopefully this idea will gain errrr ...traction and anther developer will do something similar with an plug in. I really like how you can move the keyswitch range, that's cool, especially for two octave keyboards, were you'd want the chords to sit in different ranges. When he said 'and if I do nothing, you gonna get a major chord' I was a little disappointed, especially as you can't define the key switches so there is a 'no chord' option. I'd hoped that not pressing a key switch would just play the singe note with no chord.
 
InsertPIz MidiChrds has three approaches to creating chords. Maybe I should see if I can persuade them to add a forth. They seem to have created one of the earlier versions of chorders, and although it's a bit more hands on than others (and looks less pretty, it still seems the most comprehensive in abilities.
 
Thanks Abacab

Kamikaze
That's pretty damn close to what I am looking for and is what I've described, hopefully this idea will gain errrr ...traction and anther developer will do something similar with an plug in. I really like how you can move the keyswitch range, that's cool, especially for two octave keyboards, were you'd want the chords to sit in different ranges. When he said 'and if I do nothing, you gonna get a major chord' I was a little disappointed, especially as you can't define the key switches so there is a 'no chord' option. I'd hoped that not pressing a key switch would just play the singe note with no chord.
 
InsertPIz MidiChrds has three approaches to creating chords. Maybe I should see if I can persuade them to add a forth. They seem to have created one of the earlier versions of chorders, and although it's a bit more hands on than others (and looks less pretty, it still seems the most comprehensive in abilities.
 
Thanks Abacab

I agree that was pretty close.  After reading your post, was thinking I had seen that somewhere before...
 
But that is not something that I use regularly.  That version is very basic.  With some enhancements, it could be very interesting.  But it's still fun to play with. 
 
My impression of the MIDI plugin market is that there is not enough market share to attract developers like the VST plugins do.
 
Studio One also has a built in chorder, that's more basic than the one in Waveform, without keyswitching.
 
It would be nice to find a complete MIDI chord plugin, that would do all that you have suggested! 

Kamikaze
Strummed Acoustic acoustic's key switches are strumming patterns I believe, in the similar way as instacord uses key switches, rather than voicings.
 
I'm wondering abut using program change messages assigned to keys, then changing programs in midiChords, but I'm concerned abut not off messages.
 

In Auto Chord mode, voices are modified ...