I've been involved in the buying end of these types of projects numerous times for both hardware and software in U.K. Universities. For £100k+ projects it typically goes like this:
Companies get a invitation to tender, usually europe wide. Companies submit an overview of what they want to do to solve the problem. Companies that have been in business less than 3 years or don't have a sound financial background are weeded out.
Then it's typically it's narrowed down to 3-6 companies early on. Each submits a 100-150 page tender (on paper or MS word - often with heavy copy+paste from previous bids) with prices (blind - you don't know the competitor's prices), different options etc. Each company gives a talk with a sales person and a technical person at least - are grilled by half a dozen people who all know their stuff from the customer and have different technical requirements and beliefs + management people with their own ideas. This goes on for about 6-12 months where no money changes hands and seller incurs travel/staff etc. costs.
Then it's narrowed down to 2-3 for extra implementation details and more meetings with other key stake holders - many of which have just heard of the project and often don't approve of the direction.
If you win the tender, you start getting paid in a schedule (4 or 5 big payments) depending on implementation of the project, with the final payment often 3-6 months after it's all working and live.
I would suggest if it is your business model to sell expensive products to large companies, that you have someone in sales who has done this all before.