I have developed my product completely, and have built a business for the product to be able to take to market. The product is unlike anything else on the market as of now and in my opinion would work well with a number of product lines for a lot of bigger companies.
I would like to sell my developed product to a bigger company, and I have contact with the right people that can make decisions.
But if you are not already in the market how do you know you built a business for it?Maybe you think it is a great product but you need to prove that same way your customers think.So regarding mentioned points.
1 - I think showing up a product will not put you in the risk if it is already complete,remember always that big guys are like elephants they are big and they move slowly so for them building your product will cost 10 times more money and time.If you really think it is a great product and you see that customers like it then I am sure you do everything much faster.Also your advantage is that your product is already built i do not think that by reviewing product they will do well in implementation process.
2 - You can sign an NDA but if they decide to steal something to steal from you I am sure they will do NDA can just partially defend you,but I think you should ask them to sign an NDA they will think that you are more professional.
3 - Ship that release it and see if it is really what do you think about it.If it is I am sure in very fast period you can gain recognition.
I'm going to agree with the general consensus here and say that you must develop the business yourself.
HOWEVER, if you have these great contacts, then you likely have contact with somebody who can partner with you and may even take a risk on leaving his/her position to work on a start-up. Check out this option, especially if you have a contact that can bring some customer loyalty and their own network with them.
NDA is the way I would go if you continue to approach another company with your idea. As a general rule though, most people won't pay for something they don't have to. Pretty sad. If it's cheaper to subvert the NDA with some legal ease and develop the product on their own, they will.
Some wise words from Derek Sivers "Ideas, on their own, are just a multiplier. They're worth nothing without the execution."
Check out the video here
The one thing about NDA's is that typically when pitching to a VC, they actually almost always never sign those on the first meeting because at the initial stages because they might hear 10 people with the same concept, but the trade secrets are in how you execute that objective.
Your best bet when it comes to pitching is to be very careful about who you work with and keep the details of your concept under wraps so if there is interest, in the second meeting you can have an NDA for the details of your venture rather than just the idea.
You will need customers and sales. Your question makes it sound like you have not put it on the market yet. Everyone will ask you how many customers you have. If you have no customers they will think your product doesn't work or has problems. Or they will string you along for months/years until you run out of cash and then try to buy you for a really low price.
If you have customers then you will have a pitch story to tell them. You can tell them why people buy it and use it, what people say about it etc