I found the PK-5 too short for any real bass playing...I used both feet when playing Electone and Hammond, especially when doing walking bass lines.

I see Studio Logic has a 17 note unit, but not sure of the quality, and of course, Roland has the PK-7 with 20 notes.

The best I found were the 32 note AGO Hammond pedals.

Yamaha never made stand alone bass pedals, as far as know.