Trying to see if I can recreate a site in WP with a wpmu theme?

I'm a real beginner in WP. I've created a site in RapidWeaver that's been up for about 2 years. But because we need a lot of new features that are not available in RW, I'm considering moving the site to WP.

What I'm wondering is whether I could recreate this site, or at least its essence, in WP using a wpmu theme?

I was hoping that someone might take a look at the site which is here
and tell me if it would be possible, and if so, which wpmu theme would be the best.

The site has a store, and that, of course, is no problem with all the ecommerce plugins available.

TIA for any help.
Martin