Can't find laptops with Windows 7 Ultimate - best solution?

I hope somebody can help......

I want to buy a modest laptop but with Windows 7 Ultimate. (I am a one-man business, keep my business on my laptop and take it away on business every week and want good security: I have read that Bitlocker will give me that.)

The problem seems to be that most big online suppliers don't even offer any laptops with Ultimate - I can buy laptops with Home, Pro, but not Ultimate. When I do find a supplier online who offers laptops with Ultimate, there are maybe just 2 or 3 and they are high-end prices.

Is this because Ultimate is very unpopular?

What is the best solution? Should I buy a laptop with Home or Pro and an Ultimate upgrade license and install the Ultimate myself? (I'm not an IT expert and understand it would need disk partitioning.) Or do most suppliers agree to install Ultimate for the price of the license before shipment?

Or is there a good reason that Ultimate is so unpopular and what alternative should I consider?

Many thanks in advance for your help!

I see there are separate encryption programmes like Truecrypt - is it better to get Windows 7 Home and install something like Truecrypt? Any recommendations?
Thanks again in advance for your help.

I may be wrong but I belive that all WIN7 versions can be upgraded from the device, Home Pro, to Pro, to Ultimate.

As helpifIcan mentions, most OSes can use the Windows Anytime Upgrade to upgrade your OS. But I am unfamiliar with the recovery process in such a setup, and it may not be the best.

If you check the Dell Site, and not recommending just pointing out, you can go into the Small Business section and they seem to have laptops with Windows 7 Ultimate as the primary OS.