I'm frequently starting up rails console or rails server or using other command line ruby apps. The bootstrap takes several seconds, which becomes tedious after a while.
Is there any way I can either run a compiled version, or keep it loaded using something like spork, so running 'heroku logs' runs instantly, rather than taking 10 seconds to start up?
Run a compiled version of what?
Rails server and rails console take long time to load because they have to load up Ruby on Rails plus whatever your environment requires. If you want to keep instances running then just open up a terminal window, load your console and server, and never close them.