WP blog in a subdir and want home page to take on look of the blog

Hi,
Long story short... I have Wordpress installed in a /blog subdir for a 3 year old site, with a lot of history and links behind it. This was originally and old BANS site (yeah, I know...) and it uses a crazy custom theme that displays products on the home page, while all of the real blog content is kind of behind the scenes.

I want to separate this site from BANS and take this blog to the next level.

I know I can change themes within Wordpress, but if I do so, only the /blog pages take on the new look from the new theme.

I have looked into just going to a static front page and linking over to the blog, but I want that home page to be dynamic and updated with my blog content. I'd have never gotten into this situation if I had just installed the blog on the root.

Is there a way that I can still leave my blog in the /blog subdir, but have a home page on the root that:

• Takes on the look, feel, and style from the blog's theme?
• Displays a 'home' page on the root that would be a Wordpress page from the blog?
  That way it could be edited from Within WP-Admin.
• Still show the sidebar that you would see within the blog, so that you could see pages, recent posts, other widgets, etc?
• Still have that homepage display the blog's top menu?

I hope this is coming across right, because it seems confusing to try to communicate the situation. I've been just living with this situation for a while, and would like to try to take some action to remedy it.

Any recommendations appreciated.
Greg