David:
even if that is indeed the case, the original license that allows production files to be released by others is still out there. The original license means there are no restrictions, commercial or otherwise (just attribution, share-alike, and non-use of the Arudino trademark and look) on someone drawing up the Diecimila design themselves and reproducing it...
But you know, what you're saying in your post is that there are indeed two licenses: one for the community and one for the creators. This should be made clear on the site.
I don't think we should be so worried about this manufacturing advantage: Sparkfun are the only people who've tried it, and by their good graces they recognized that the project's success is dependent on trust and collaboration. I'm thinking other poeple should be let into that ring of trust 
I also have to ask, if, as you say, the Arudino team is "not bound by the terms under which they license to others", then what is it they're actually offering to release as the basis of this open-source project? Just the schematics?
D