What sort of method would be used to cluster those, statistically speaking? Like, given a data set like that, how would you determine if the distribution is multi-modal or unimodal?
Mean shift clustering, for one. This short PDF provides better insight than wikipedia. Does NOT require you to specify the number of clusters like in K-means:
http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/TUZE...
http://en.wikipedia.org/wiki/Mean-shift
Example python code using scikit-learn: http://scikit-learn.org/stable/auto_examples/cluster/plot_me...