I think it's a great idea. Is the OBJ based on anyone else's work - be it a laserscan off someone's helmet, or someone's already-existing 3D model? The reason I ask is that we still need to protect people's tremendous work investments, otherwise it runs against the culture of The RPF. In many cases, if it's an OBJ that someone released into the public domain, it shouldn't be hard to track that person down and ask if they ever did a 3D printable version, or ask them if it's okay to do so. However, if the artist wanted to only share it as-is and you turn it into a business beyond their original intentions, you can see the reactions of RPFers in other threads whether or not they feel it's a good thing.