I was just looking around myself and found:
http://www.fusioncharts.com/demos/gallery/#funnel-chart
One drawback is that the free version only renders in Flash and the paid version is $399 for a single license!
A free library http://www.jqplot.com/ seems to handle funnels in JS. eg:
$(document).ready(function(){
s1 = [['Sony',7], ['Samsumg',13.3], ['LG',14.7], ['Vizio',5.2], ['Insignia', 1.2]];
plot4 = $.jqplot('chart4', [s1], {
seriesDefaults:{
renderer:$.jqplot.FunnelRenderer,
rendererOptions: {
showDataLabels: true,
dataLabels: ['47 years', '28 years', '22 years', '14 years', '7 years']
}
},
legend: {
show: true,
placement: 'outside'
}
});
});
Other people have "hacked" together a "solution" in google charts by centering a bar chart: Centered bars on a Google Chart BarChart?