In the main install directory, there's an XML file called "startdlg" which lists out all the examples and templates. Remove the blocks of XML corresponding to the items you'd like removed from the starting dialog.
Thank you so much!
This did the trick. I removed everything apart from:
<?xml version="1.0" encoding="utf-8"?>
<name>New empty project</name>
<description>Create a new empty platform-neutral project with default settings.</description>
And now I only get the template for "New empty project". Which is exactly what I was hoping to achieve!