Two blogs, same dynamic sidebar

I’m running two instances of WordPress using separate databases. #1 is at the root level of my host, #2 is in a directory that can be directly addressed.

I would like to be able to have the same sidebar on the two blogs. getting the dynamic lists of one blog to another.

From what i have seen from the wordpress file structure, i would need a modified set of wordpress funcctions wich would accept a specific database as an argument.

Are there other ways?

Plugins? A dedicated php file that could generate the sidebar and be embebedd through php on the second blog template?

Have tried it? Please do tell…