R – silverlight and sharepoint restored site

It sounds like a timeout is the best lead you have.

I believe there is a fairly firm timeout for operations. I haven't seen this in web parts, but have seen it in custom Visual Studio workflows within SharePoint where the initial activity on a workflow performed a somewhat long running process without getting the workflow to sleep first and become asynchronous. If I recall correctly, the timeout is 2 minutes.

I just did a quick search which yielded this link which confirms that and tells you how to tweak the timeout.

In the end you need to minimize the rows and maybe the sites (SPWebs) that are being queried. If you aren't using it already, I would look at SPSiteDataQuery or SiteData.asmx to help with your query.

After emailing Tim Heuer, I was informed that is not possible in SL3, but will be in SL4!