Woah, easy Diki! I wasn't referring to songstyles in the traditional sense of a song-specific style. What I meant was this:

Let's say you ARE using two arrangers MIDI'd together. Let's say Arranger #1 is a Yamaha Tyros, and Arrranger #2 is a Roland. Many of us have this in our closets!

On Arranger #1, you create a custom "style" consisting of your favorite chord progressions: C, Am, Dm7, G7 or whatever. ALL this "style" would consist of, is one MIDI channel containing triads or tetrads of the desired chords, and another with the desired bass note. Record at a slow tempo. No drums, etc. Let's say this is just style Variation 1. You could make the progression as long as 32 bars with some embellishments toward the end, because you don't always have to let it play through and loop. If you NEVER want it to loop, you could create your chord sequence an ending, or even an intro. You also have three other variations at your disposal!

Now Arranger #1 MUST be a Yamaha or Korg because those brands allow you to designate a style track as NON-TRANSPOSING. I.e., with the proper settings, the track's pattern is ONLY affected by the Master transpose. So if you create your "style" in C major, you can use it in any key by changing the transpose on Arranger #1. So what you've really created (using my example above) is a generic I, vi, iim7, V7 progression.

The output from this Yamaha "style" is fed into the NTA (Note to Arranger) channel of the Roland via MIDI. Many guitarists and accordionists are familiar with this approach. Ideally the MIDI clocks of the two boards would be synched, but the system will still work if they're not. Because all that really has to be transmitted are note-on and note-off messages. (That's really all ANY Chord Sequencer does... it's not magic!) Also, if the custom progression is recorded at a slow tempo, it might sometimes be useful to play it back in double-time.

On the Roland, you can set up two adjacent "performances" or "user programs." One is a standard LH live chords, RH melody configuration. The other could move the split point, and summon the MIDI set where the input to NTA drives the chords. Now you can play "Piano style" or modulate SN guitar sounds across the whole board ("Split" would be moved out of the way to the far left facilitating two-handed play.)

With the above arrangement, the style controls on the Yamaha become your "Chord Sequencer." You can restart a lenghty variation after just a few bars, or let it play for more if you included some jazzy "color chords" toward the end. You also have 3 other variations, intros, endings which could summon different progressions corresponding to the chorus, final verse, etc., on command.

By using the adjacent registrations on the Roland, at any time you can toggle between "live" chords or "canned" chords being driven from the recorded progression. This approach gives a whole new meaning to "faking it!"

For the next song, you would choose a different custom user "style" with its corresponding triads and tetrads. However, many songs share and can be played with the same common chord progressions. You'll probably have to create your generic progressions in at least two different time signatures, 4/4 and 3/4. But with flexible tempo and the drum beat supplied by the style on the 2nd board, the time signature isn't as important as one might think.

If you don't want to use style variations to store and summon your chord progressions, you could also use simple two-track MIDI "songs" formatted in a similar way: triads or tetrads on one track and bass notes on another. In this case, the desired progressions would be recorded sequentially end-to-end, rather than as parallel style variations. The Tyros specifically allows you to mark up to four positions in a song, and jump to them immediately. So it's almost as flexible as using non-transposing style tracks. I think Roland and Ketron both made MIDI file players with this kind of mark-and-jump functionality.

Bottom line, most arrangers still don't have a chord sequencer. But connecting two arrangers (or an arranger and a decent MIDI song player) to each other lets you approximate this functionality. You definitely don't have to be a genius or program your own arranger from scratch. Just make imaginative use of the tools that are already there!