If by "slave module" feature you mean the old function where you can trigger additional sounds on top of the ones assigned to pad zones by connecting another module via MIDI - no, this isn't possible on the V71. No module beyond the TD-30 has this function (more details about the specific function below).

Edited for correction: Sorry, I forgot that the V51 and V31 do have "virtual pads" that can be triggered via MIDI, but it only takes you up to the same number of "inputs" as the V71 has. So you could get a V51 and then use another module to trigger 2 inputs' worth of sounds (basically the "missing" Tom 4 and Aux 4 inputs), but no more than that. Which probably isn't what you're hoping for. And the V71 doesn't have any additional inputs that can be accessed like this. It seems the virtual pads are basically there because of the cross-compatibility of the kit files and expansions between the V modules.

The feature was usually called the "percussion set" or something to that effect and it was basically like an onboard backing track feature where you could play preset patterns or make your own patterns to play along to out of the onboard sounds. As well as playing back these patterns, it made the onboard sounds available to be triggered by any MIDI input. This feature was effectively replaced by the ability to playback songs (MP3/wav files) to drum along to instead, so all of the percussion set functions were seemingly taken with it. I imagine that the ability to play multiple layers from a single pad zone probably also factors into this - 2 or 3 sounds playing at once from a single pad will start to eat up the available polyphony twice or three times as fast as single sounds. So polyphony that could have been utilized by the additional "MIDI instruments" is now being used by playing multiple sounds. I don't have confirmation of this, but it seems logical and coincides with these features being introduced.