Can an Input event be 'faked' with a script?

You know how you can use the Input Manager to define an event like "Jump" which the user can assign to a key? Is there a way to then programmatically create a "Jump" event? I know I could call the appropriate functions directly, but if these events are handled in several script or ones I'd rather not muck with, it seems like faking events might be cleaner.

Specifically, I want to make some on-screen buttons that mimic keyboard buttons, so pressing the mouse over the on-screen 'left arrow' key would do the same thing as pressing the actual left arrow key.

Just abstract it:

function Update () {
    if (Jump()) {
        // do jumping
    }
}

private var doJump = false;

function Jump () : boolean {
    if (Input.GetButtonDown("Jump")) {
        return true;
    }
    if (doJump) {
        doJump = false;
        return true;
    }
    return false;
}

function DoJump () {
    doJump = true;
}

Then call DoJump when an on-screen jump button is clicked or when you want to "fake" it. If you have jump input handled in more than one place, always call the Jump function instead of checking input directly.