The Casio Casiotone MT-100 has 8-note polyphony, a 49-key keyboard, and 20 instrument patches!  For rhythm, it has 12 different programs, plus an analog percussion generator (bass drum, snare, 2 toms, and high hats, etc). It also features both fingered & Casio Chord accompaniment.

Fun Fact: The MT-100 is used by They Might Be Giants!

The MT-100 has 20 instrument tones:

Celesta, Organ, Pipe organ, Flute, Clarinet, Trumpet, Horn, Oboe, Accordion, Violin, Cello, Piano, Electric piano, Harpsichord, Vibraphone, Harp, Mandolin, Electric guitar, Funny, Cosmic tone