Excel 2007 : circular clock style chart

Hi,

I am looking to make a chart that works like a cross between an old fashioned clock and doughnut chart. I have seen some speedometer type charts that may work, but am having real issues getting this enetred.

What I would like to do is take data from a pivot, and chart according to running total etc. i have attached a drawing of the idea we have and know how to do the half circle version, but really want to do a cahrt where there are 'clear areas'.

i think this may be able to be done by looking at the data and adding the zero value and making the total a fictional number and making the difference chart as 'white'. I hope that makes sense (eg if have to do 70 quotes in the month, outside doughnut would be 2 data points one of 70 and one of 30, the 'pointer' would then look at the number reached from our sql report and add in as the clock hand)

Am I perhaps wishing for too much, or can anyone suggest a way of looking at this?

Thanks

Louise