I have a global product presentation website myproduct.com

For certain countries I also own the country domain: myproduct.co.uk, myproduct.com.au, myproduct.es, myproduct.de, etc.

The presentation website is translated in multiple languages and I set up redirects: myproduct.es will redirect to myproduct.com/es/, myproduct.de will redirect to myproduct.com/de/, etc. .

The content so far is the same, just translated in different languages. The advantages are that it's easy to keep the content aligned - everything is managed from one centralized dashboard (I'm using Wordpress with qtranslate).

Now I'm running into trouble as for different countries I want localized content - for UK I want to run different promotions and use a different reseller than for .com.au so I would like that users coming from myproduct.co.uk see something different than those coming from myproduct.com.au (and not be redirected to myproduct.com as they are right now).

How can I achieve this?

1. I could duplicate the whole main website and modify only certain parts but then I would have a lot of duplicate content (e.g. info about how the product works) and I would have pages that are likely to change (FAQ page) that I would have to keep updated over all websites.
2. I can duplicate only partially the main website: on the localized website I would have only the pages that are different and then all other links would point to the .com site. This would solve the duplication problem but would cause confusion for the user as you would navigate from .co.uk to .com without noticing and then wonder how to get back.
3. Other, better option?