bluetooth marketing software

we need to build a bluetooth marketing application windows based to send bluetooth messages. example bluemagnet or bluemarket we need to send images, text and send text message with question and receive answer. we need to have an application usable in unlimited clients without license limitations so we decide to build it. We are looking for a long term arrangement with someone who can update this now and then work with us with all updates in the future. you must have some working software which will be tested to check your knowledge.