Please help! Need suitable wordpress theme for business info website

We are looking to create a simple information website using wordpress. I previously posted asking for something simple and user friendly as we are newbies and we we're recommended Canvas.

However it seems that the architecture we would like is not as simple as we first thought and we've been advised that Wordpress itself may not be suitable

Essentially the website will be a database of information. We will have a home page with, we hope nested pages (a-c, d-g) etc on the left which when clicked on will expand to list all the companies. Once the visitor clicks on their company they will be taken to a new page with a short menu bar across the top (retaining the nested pages on the left) with 5 tabs linking to pages containing info relating to that company. Each company will have the same information page options for them, each containing relevant information for that particular company. So i guess it's like a subdomain for each company. does this make any sense?

Could anyone suggest a wordpress theme that would be suitable for this? We need something relatively simple, that has good support. We will be fine adding widgets and plugins but I think writing lines of code will be beyond us.

If what we want to do is going to be difficult in wordpress could anyone suggest an alternative web builder that might do the trick? the overall aim of this site is to drive traffic, so it needs to be very SEO friendly and good for advertising.

Any suggestions would be much appreciated.

Cheers