Creating KPIs requires a calculation module, that accesses incoming performance data and applies mathematical formulas to create composite data points.
Livestatus provides methods for doing sums, averages, but is not really meant to create new data points.
Typically performance or state data is received from plugins. This data is captured through Livestatus, the calculation module applies a real time formula and sends the resulting data point back to an arbiter as a passive data feed which matches up to a *service* or new type of data point such as calculated service.
This way the calculations can happen on a dedicated host if required and have it's own UI or integrate the UI with the Shinken UI. If it was a generic UI just for calculations it could actually be used with Nagios Core as well.
This would be complimentary or integrated to an CEP module (ex. ESPER). It should be evaluated.