Recently ran into a problem where we needed to mass delete lots of unpublished nodes (over 1500), but the package would timeout - adding connection timeout to the connection string in web.config did not work, but adding

sqlCommand.CommandTimeout = 1000000;

after

SqlCommand sqlCommand = new SqlCommand(sb.ToString(), sqlConnection);

fixed the timeout (inspired by something I noticed in the memberexport forum), but also needed to add 

<add key="aspnet:MaxHttpCollectionKeys" value="2000"/>

to webconfig to enable deleting of all the nodes at once, also added a new amount to the dropdown to allow us to load all the items on one page so we wouldnt have to page through lots of pages!

Just thought I would put this here so if anyone else has the same problem, they might be able to do the same :)