Is it possible to get list item individual permissions using a web service? This is for SharePoint 2007, I've come across a couple of articles that say you can't but was wondering if officially documented anywhere
The articles that you have read is correct, only the Web service that provided in Office SharePoint Server 2007 to manage permissions is
/_vti_bin/Permissions.asmx that provides methods for working with the permissions for a site or list level permission not the list item level permission.
Regarding the official link, check Web Services Access for SharePoint 2007
The link provides all web services in SharePoint 2007, where there is not any web service to get list item level permission and this considered official evidence.
Workaround to do that is to create a custom web service that get list item level permission as mentioned at Item level security with SharePoint web services