Creating content regarding to node address arguments
Path aliases must be exact, thus if you want my-fancy-page/tt3741 to work you need to create an alias for it. If you link to the node path node/6 then node/6/tt341 will work. This has to do with how hook_menu works vs how path aliases work.

If you wish to hack around how path aliases work you can try out the PURL's Path Extensions feature http://drupal.org/project/purl or use hook_url_inbound_alter() to get the correct node given the unique alias. 

Boost will work as long as each URL is unique (same as drupal's core cache). Good luck.