Multiple Version Of One Website

Hi,

I built a website for a client recently (powered by Wordpress).

They now want to build / clone a further 5 websites for each of the countries they operate in.

I was thinking of using a multilingual design / approach however the client wants to change a few other things on each website too:

- content on each page is different for each country
- products for sale / availability is differnet for each country
- the menu structure is different for each country
- slightly different home page layout for each country

I know i could probably achieve all of this with a multi-lingual plugin, however i know the client will want to change somethings (page structure) in the future for various different countries so i was thinking that it might be best to just clone the default site 5 times and set each country as a sub domain, and then tweak each of the sites from there:

www.domain.com - a simple page that asks you to choose your country (and remembers it)
uk.domain.com - for English customers
ire.domain.com - for Irish customers
us.domain.com - for American customers
au.domain.com - for Australian customers

What's your opinion on my approach? Thanks in advance for your help.