It looks like there are a few Multi-Effect types that might help-- Tempo Step Phaser (I'm not sure about this one, but it sounds like something I'd want to check out), Tremolo 1 or Tremolo 2, and Tempo Slicer.
You might also get some interesting results using one of the Delay types, perhaps in combination with one of the Multi-Effect types suggested above.
As for an arpeggiator, if you can connect to an iPad then perhaps there's an app for that?