There is a store procedure called "editDeleteChilds" which take a page id. Call that with the pageid of the recycle bin. Be sure to backup the database before doing this, if something should fail... :)
You can set the timeout on siteSettings with databaseQueryTimeout http://sdk.episerver.com/library/cms5/html/P_EPiServer_Configuration_Settings_DatabaseQueryTimeout.htm.
And if you set debug to true in web.config you will not receive a timeout from asp.net.
Since there is an issue with the Recycle Bin for us, after applying a bunch of patches in order to get CMS6R2 to work as it should, we cant delete pages from it in edit mode without getting time out. Weve set the time out in the config without any luck so we hope we can do it with an SQL query. However EPiServer removed the script for deleting pages only in the recycle bin in this version and since we arent EPiServer engineers we dont know how to specify to only delete the pages in the recycle bin. The only script ive found is the editdeletepage which are close to what we need but im guessing its for a given page and not all pages in the recycle bin.
Is there a kind soul which could help us with this issue?