We have a multi-tenant deployment as well and find the reporting is a big challenge. LEM is quite good at collecting and reporting on events IF you have a very simple deployment for a single tenant (i.e. not an enterprise level product). After many hours toil with LEM Reports I found a way to create custom filtered reports (not for the faint of heart so be warned).
I'd recommend checking out the following thread - Reports by user
...and the following KB (although I'm still looking for a way to edit the file properites to get this to display correctly in LEM Reports console) - http://knowledgebase.solarwinds.com/kb/questions/2692/Creating+a+Custom+Filtered+Report
Good luck getting what you want from the reports, I'll follow this thread and if you need any pointers then just reply and I'll get back to you when I can.