you are walking a fine line with this one. Without a trademark you run the risk that no matter what you do and how you present it the company could take it and not give you any compensation. Personally I would not present it to the company without a trademark, it could backfire too easily. As far as how to market it to someone else, I'm not really sure but what about talking with some other furniture makers and trying to get a feel for if it would fly without giving them too many specifics.