Turns out this was really simple.
When running the Passenger Apache Module, there are a number of configuration variables you can add to your virtual hosts file. Somehow I missed the documentation first go around. The solution ended up being as simple as adding this line to my vhosts file:
PassengerRuby /home/{user}/.rbenv/versions/2.1.0/bin/ruby
All is good now, hope this helps someone else.