The equivalent in Studio One would be dragging the track into Sample One and looping it inside of Sample One. But, really, is pressing "d" in Studio One too difficult? You just have to press "d" to duplicate the clip as many times as you need it? Pressing "d" aligns the duplicates perfectly.
Alternatively, you could also use the arranger track, again you just have to press "d" to duplicate the arranger sections.