Advanced charting features

Is it possible to have multiple series in one chart like this:
http://www.chartjs.org/docs/#line-chart

or stacked bar chart:
http://www.highcharts.com/demo/column-stacked

I’m having a good time playing around with Metabase but I’m definitely needing some more advanced charting features.

We have stacked bar charts, and an open ticket for multiple series on a chart at https://github.com/metabase/metabase/issues/656

Have you tried to create a stacked bar chart by splitting along two dimensions and selecting “bar chart”?

It's been a while, but we shipped 0.15 yesterday, which has multiple series.
http://www.metabase.com/docs/v0.15.0/users-guide/09-multi-series-charting.html