Please note that Joomla! articles are used in the examples of the documentation because they are the most common target for this extension. However, that does not mean that Simple Custom Router works only with Joomla! articles; it can be used with other Joomla! extensions too (although it does not work with every single Joomla! extension).
Where can I get the version for 1.5?
You can use this version for Joomla! 1.5:
It has the same functionality as the version for J! 1.6/1.7.