Is it possible to build a dashboard that will take user input, runs serveral searches, and displays multiple graph outputs? ... Without using post processing? the 10,000 post processing limitation is a deal breaker.
Sure, if you download the ui examples app, then take a look at "lister driving multiple element" app/uiexamples/advancedlistermultipleelements
Essentially you want to have user inputs, have a child ConvertToIntention which will allow you to put the input value into children searches. Take look at the How to user lister modules and the lister module specification
Switchers also may be of use