This will give you some practical and simple step input functionality.
Step Input and Step Sequencer are quite different thinks I think ...
There were some free old Environment Step Sequencers
here, but I had no time to check if they are compatible with Logic 8/9 and if they need re-design. Honestly it will be more easy for me to make new complex Macro St. Seq, which will be new generation and will support much more presets - say 64, which can be controlled externally via Program Change, CC#, support internal clipboard, presets management etc...