Generatewhatsnext, thank you for your suggestions. Especially for the last part of your post, this is what i was also afraid as he has the skills/machines so my “concept” could possibly become a real piece of furniture. For this reason, i charged a biit more this first phase of concept generation as exactly he could say that he takes over from there. For this reason included terms and conditions in the contract that would not allow him or anyone else to work on this project and only me and my partner could develop/oversee this project. Do not know if these were wise decisions but this is how i thought i could secure myself in terms of the fee and the design quality.
Singletrack. I can really imagine the feeling as with another case i experienced a similar situation. As long as they do not use your name as "designed by… " it is just the designer’s feelings that get hurt 
if though they put your name on it then hmmm… it is not just about feelings.
HOWEVER! (update) after sending last week a Plan about the process we could follow for the project (steps) and the contract that i would like him to sign the guy never replied (last Thursday). I sent an e-mail again on Tuesday to check if he had the chance to review the docs etc. and again no response.Not even you know “thanks i will have a look and will get aback to you” (even if he never does… just be polite…) … Ahhhh… once again… Same old story. Really hate it when potential clients are talkative etc. but when they receive stuff such as contracts/fees and so on they disappear. Now i do understand the kind businessman he is and if he (ever) gets back to me i am not sure if i would like to collaborate.
This kind of small details are extremely important for me and i think from these you can see where things will go with this collaboration.