Not that I have much experience doing this, I would think selling the entirety of a product including IP is quite a tricky process for which there is no real template in terms of how you should go about it. I know it definitely happens in the sphere of enterprise software where it is usually smaller companies selling some software which large firms have found happens to suit their needs at a particular time. But I think establishing those kinds of interested contacts would take time and a careful awareness of opportunities.
It might be worth considering other possibilities in terms of generating revenue, perhaps by licencing the platform.
It is frustrating when you have a good piece of technology / application and you know it would be useful somewhere, but struggling to make that sale. If the economy was in better shape, larger companies would probably be much more willing to invest in full software / IP acquisition.
One other route is that of making some aspect open source but sell consultancy and support.
I would definitely be interested in any success stories of the kind you are hoping to achieve.