tedster - 4:20 pm on Jul 7, 2010 (gmt 0)

1) can I remap subdomain URLs to the relevant pages on the www domain

If you mean a server mapping, then you have exactly duplicate content for each geographic target. It would not be localized in any way - currency, idioms, etc.

If that's the final result, I don't see that it's worth the effort. If you really intend to target a location, then I would suggest the trouble of learning to "speak like a native" of that area.

I once worked with an automotive site that was originally for the US but wanted to reach the UK. The vocabulary differences were quite extensive. I've also learned that in the UK, collective nouns or names of businesses take a plural verb, whereas in the US they take a singular verb form.

US: Google is...
UK: Google are...

So if you really want to reach the visitors, and not just rank in their search engine, some localization is needed.

2) can I geo-target each subdomain in WMT to let Google know where I am aiming each subdomain and finally

Yes - just set up and verify each subdomain as a "website".

3) would that lead to dupe content issues?

Dupe content is all about filtering out all but one version for any specific search. So that would happen, but it wouldn't be a problem or a penalty.