Would it be worthwhile just creating a new class outside the IoC and then make a repository for this?

Not a clue how to do that.

Have you created proper routes? Also, do check your error log to see if the IPN hit is an error.

I created the route as author detailed: https://github.com/logicalgrape/paypal-ipn-laravel

Tested the route using IPN tester. Paypal returns route as fine but database doesn't get touched.

UPDATE: The package supports Paypal IPN out of the box, with even some additional security checks. Nothing to do from your side.

In case of Payum there is a package PayumLaravelPackage (was finally released few weeks ago) and there is a get it stared doc. It uses Paypal Express Checkout as how to use example by the way.

Payum itself provide support of Paypal IPN but the package does not provide such integration yet.

With a new Payum version (0.10) it would support Stripe.Js and Checkout too.