I like the Boss ME-50 very much. And as weird as it may sound, there is also the bass version (ME-50B) that could fit... I encourage you to try it on!
-Roland JX3P+PG200, D50+PG1000, Juno 6+106, MKS50, JP8080, U220, MVS1, MDC1, MSE1, RS09, TR-707
-Korg Poly61M, M3R, MicroKorg, Micro, Kaossilator/Pro, Monotron X3
-Yamaha DX7, TX816, TX81Z
-Crumar Performer, DSI Mopho, SCI Prophet 2002