Large Company looking for a website and web presence overhaul

I have large company here asking to suggest a vendor to help them with a overhaul of their current site(s). This is potentially a huge project, that they are looking to get rolling very soon with, this is also probably long term project. It is a big company with offices in several states and branches in multiple countries. I thought this would be a great drupal project.

Here is some more info:

Visually we want the site to look more modern and have clean, intuitive navigation.
On a broader scope, the site is going to encompass our 2 legal entities. We have 4 divisions- consumer, healthcare, commercial and contract. Each of these divisions has its own unique set of needs and separate markets. For example, Consumer will need mini branded sites, Healthcare needs a resource center for posting clinical data, Commercial sells to restaurants, schools, etc...and will need sales materials posted for their sales reps, & contract has their own needs that are still being determined. We also have a customer support system that can benefit greatly by having order tracking and other tools online to reduce the manpower required. Our long term goal is to link the site with our internal database to give our various customers and sales teams access to information that is currently retrieved manually.

Not only do we require our vendor to be technically proficient, we are also looking for someone who can work with us to develop our “story” and effectively communicate to our various audiences. It is a very large project encompassing many aspects of web design and development as well as the ability to create a strategy for our brand positioning and other marketing concerns.