Adding a custom item to the shopping cart...

Is this possible? I want to design my own configurator that would help choose items based on my custom logic.



However, I don’t know if the following is possible… Can I add an item to the shopping cart, an item such that does not exist “physically” in the store but only in the shopping cart… ?



Say, I want to add an item “Blah 125 for $455.99” with description “Blah blah blah”…



Doable?

I doubt it since everything is associated with an id.