Andy,
Unless you know something I don't know about Robbe's business plan (if there is one), and you are assured they no longer will produce those items, knocking off their product is still wrong.
What rational will you employ to justify pirating to those who (may) buy the U-47 tooling with the expectation of producing a unique product for sale? By making the parts less 'unique' and unattainable through fan-based tool and part making, you kill the incentive Robbe or another company has to continue production of the kit (and support parts) at a later date.
Once all we baby-birds have fed ourselves we no longer have a use for mother-bird, and she flies away forever.
David