I am searching for a multivariate dataset consisting of vectors (no time series) for clustering experiments. It should have about 8-20 numeric features (non-numeric would have to be ignored by me) and about 100-500 instances. Having some labels additionally might be useful, but is not required.
I have worked with the 2011 Irish Census dataset for clustering and demographic classification previously and found it to be very useful.
There are various aggregated levels you can download the data, some of which are in your 100-500 instances range. There is also a fairly comprehensive data dictionary available.
There are no labels but mapping your results (boundary files are also available) would provide some sort of clarification (you wouldn't expect a cluster with high proportion of farmers to be in an urban area).