This is not a job for InsightIQ in the current release although I would expect that this type of functionality will eventually be added.  Today, it's a job for the command line.

From the command line it's as simple as:

# isi quota list --format csv --type directory

Store it where you want, process it however you want,and email it to yourself if you want to do that too.

Personally, I find it more useful to use Graphite (pick your tool of choice) and feed it parsed quota data.  That way I have a continual graphs of the data.  Google "isilon graphite" for examples.

InsightIQ 3.1 with OneFS 7.2 may have what you want. Few of the features in IinsightIQ 3.1.

Welcome to InsightIQ 3.1 

Quota reporting

You can now view information about quotas created with SmartQuotas. You can browse the file system to identify directories that have quotas applied.  You can then select the quota you want to view.  InsightIQ shows the usage on a directory, relative to its quota limits, over time.

Usable capacity reporting

InsightIQ now offers an enhanced view of the amount of space remaining on your cluster. Including snapshot space usage, virtual hot spare reserves, and estimating protection overhead, InsightIQ can now provide a more accurate indication of how much data can be added to cluster before reaching full capacity.

InsightIQ 3.1 White Paper.

In conjunction with the InsightIQ 3.1 release, a new white paper is available that discusses the various charts and graphs in the performance reports, and provides guidance on the metrics each chart displays and how to interpret them.  This white paper can be found https://support.emc.com/docu57796_InsightIQ-Performance-Reports-and-Graphs-Technical-Note.pdf?language=en_US .