The SFX-6 was made publicly available in September 2003. It was actually the first version of the Monomachine as the keyboardless tabletop variant was introduced a few months later.
A lot of attention was drawn to the looks of the SFX-6. In contrast to more common synthesizer designs, the keyboard and the control area of the SFX-6 were separated in two distinct sections. The intention was to allow two musicians to jam together using a single synthesizer. One of them would be in charge of the keyboard while the other one operated the sequencer and adjusted sound parameters.
Getting hold of a Monomachine SFX-6 today can be hard, but there's no reason to despair. A MIDI keyboard connected to the SFX-60+ MKII will provide more or less the exact same functionality.