Arpeggiator/Chord Bank

I know the idea of an arpeggiator is to break a chord into a series notes and you can use a pattern triggered by a base note to play notes with predetermined intervals (pitch and timing) , but how hard would it be to turn that into a MIDI chord machine.   
 
Say I call up a Maj9 pattern; when I play a C# it goes through the arpeggiator and outputs a C#Maj9.   It would be a simple matter to build a set of patterns that define specific chords/voicings.  If the arpeggiator's interval/rate parameter could be set to 0 and adjusted in mSecs, the current interface could play all the notes of the pattern simultaneously and--voila!--making chords.  Increasing the rate by some number of mSecs would create strums. 
 
I know there are 3rd party products--e.g. Cthulhu and MidiChords--that integrate chords with either strumming or chord generation, but wouldn't it be convenient if it was merely a matter of choosing settings in the existing MIDI Track Inspector?