unless @123toid has a different suggestion id say make a pair of his soundstage 15 (plans in the forum webshop) and power them with DSP and a 4 channel amp that can bridge 2 of the channels. use the bridged pair for a subwoofer to get more power handling (bass power is what gets people moving more than volume in the mids/highs)
a subwoofer to go with them is something the forum can help you design based on driver availablity and how much budget you have left after building the soundstage 15s and buying the amp
although they can play down to around 50hz crossing over the soundstage 15 with the subwoffer as high as 110-120 hz will get more of the bass frequencies in the subwoofer which further helps with giving energy to a crowd of people (at the potential cost of some sound quality but this matter less in crowd playback vs home theatre single person listening)
