The concept is good, however the reality is slim. The Tyros has so many functions features, buttons, huge screen adn everything else making a rack module would be like 8 spaces! An arranger rack is almost unheard of due to the control of an arranged song via a rack would be hard to operate. If you really want 76 keys can you run the real Tyros as a module and use a midi or usb as a controller with 76 or 88 keys and so on?

Phil