I take it is possible to write a Pronto Script to lock out the remote functions after a set period of time.

What I would like is the Pronto TSU9600 to run for a set time - days, weeks, month etc.
and then stock the remote working until either the script is removed or preferably a pass code is input to remove the lock out function.

Is it possible or something that would be too hard to implement?
Having no experience in Java Script limits me severely in achieving this.

You could analyse getDisplayDate() and use Widget().visible to disable functions and show a enter code button when it's later then a date. But changing the Date can be done in the remote, so working around it would be easy, maybe you could use TCP to check the time every half hour. The unlocking code would cause that everytime the remote would be reset (or empty) the code would have to be entered again.

You would do this type of functionality something like a "splash" screen that's mentioned in the Dev Guide such that if the user returns to the 'Home' page, one condition of home initialization is that a full-page widget is displayed that asks them to enter a code.

This whole solution hinges on the 'System.setGlobal()' functionality that will be erased with a firmware update or with a reset of the remote. Therefore, to do a solution like this, you will likely want TCP connectivity as SWORDS mentions and you might want to build "pronto licensing" per se into one of your public websites. Each config you develop gets a key and in order to access, you must hit the licensing website. If licensing passes, then home page can be made active. If not, then pop up the full page widget asking to contact the vendor.