Actually I was thinking of applying a heavy tax to blocks bought with the blueprint, that way buying blocks at shops would be a lot cheaper.
They just added buying with blocks as the vanilla default today. I'm thinking it will make decent ships a lot less disposable than they have been (which seems kind of neat to me for a number of reasons :D )
I agree though Keptic - I think they should have the ability to allow players to opt to pay for blocks they don't have at a mark-up -- I'm thinking they could jack the price up like crazy and possibly impose an additional delay for those blocks (when they implement the planned shipyard idea) to mimic material handling and transit time associated with having to special order resources that aren't on hand.
Thus everyone is still encouraged to craft and/or procure resources -- but credits still hold value and it's still possible to get a certain blueprint when you *really* need one but don't have every single block you need.
I also think it'd be cool if you could opt to substitute blocks in the blueprint (like using blue hull instead of standard red armor, as an example). This could allow you to get around some blocks you might not have as well as dynamically change color schemes on a blueprint without having to spawn it in at full cost only to painstakingly replace the entire hull.