Yonac Software has released Shredder 1.1, which now has an added ‘Chordmaker’ feature.
With Chordmaker you can create up to 4-interval chords for each note, or choose from 17 built-in chord definitions. You can also transpose on the fly and save progressions to file.
To play chords, you simply pick the root note on your guitar.
You can also use Chordmaker to control other virtual MIDI compatible apps (such as ORGAN+ seen here) by sending out auto-formed chord messages.
Shredder is available in the App Store.