In the built-in example: Examples-Instruments-Physical Modelling-BarModel, one of the presets is called 'Rhodes'. This is not terribly close in sound to the example, it's more of a bell-like Rhodes with the pickups set further away from the tines. In the audio example you posted I think the pickups are closer. Anyway, the Cabbage example uses bar stiffness to control pitch - you can see how note numbers map to different stiffness values. I don't think that the opcode offers any way of changing the dimensions of the bar. Tonally the opcode is quite limited so I don't think you could get the 'honky' sound of the SoundCloud example, you'd probably have to code something more from scratch.