php/asp/netdynamics

I'm looking at using the above for a web application on  SQL Server and
Informix databases, running on IIS.

It needs to be customisable - the main concern is that I need a client to be
able to select which fields to show on a page, so one might want day totals
to show, another may want day and week totals, another just week totals.  

Could anyone tell me which technology would lend itself to solving this
problem and the best architecture to use - application variables/database
fields?

Can you use php to create COMs?

Appreciate it

Russ