Same content, different themes using subdomains – is this possible?

I’d like to be able to use WordPress in the following situation:

1. I need several ‘sites’, each with individual themes to distinguish them, probably using subdomains of one main domain.

2. Each site will have the same content (categories and articles), possibly with a few pieces of unique information specific to that site.

3. Each site will have its own bbPress installation.

There are 2 options for me.

1. Create the first site, then duplicate the whole thing each time I need a new site (changing theme suitably each time). If an article is added, all sites need updating. This is technically ‘easiest’ but laborious longterm.

2. Use the wp-subdomains plugin or multisite to create the whole thing in one installation.

I’ve spent quite a while reading forum posts and googling to see if anyone else has asked the same question as option 2, but can’t find anything.

I’d really like to know if it was theoretically possible (or not!) using existing plugins / software before I spend a lot of time testing it out, so any hints or pointers in the right direction would be gratefully received!