Excellent advice from Tim.
I would take the risk and do the design, specification and quote for free. I would present that package to the developer and their team, but I would not leave any information behind. If they want the design, spec. and contract left behind to contemplate it, then I would insist on a fee of 10% of the value of the project. You wouldnt catch an architect leaving behind their plans without a contract or a fee being paid for that work.
If the developer is in fact tendering the job out for bids, then they should have a package available for all bidders that fully describes the scope of the work etc. This ensures a level playing field between all bidders.
Chris, you may want to look at this as a marketing opportunity. To get the chance to do this work, and put it in front of the whole community will only do great things for your business. I have direct experience in a situation much like this and will discuss it with you privately if you want.
Have a great day.