Fields of Blood is good at what it does, but yeah, you might find some other supplements more useful.
Dynasties & Demagogues (by Atlas Games) might help somewhat.
I think Mongoose Publishing came out with something along roughly similar lines - Strongholds & Dynasties, I think.
I agree with Allandaros, and what's more, there is a 3rd ed. conversion site for Birthright:
http://birthright.net - it's got the 3e PDF available for free download, as well as a good forum for further info.
Of course, Expeditious Retreat Press offers the excellent A Magical Medieval Society: Western Europe. It's specific, sure, but a good amount of the data is usable outside of the default "magical medieval" assumptions.
I'm not certain exactly what you're intending to run, so I'll leave off giving any further tentative suggestions.
edit --- and as far as premade adventures go, I just don't know of any, off the top of my head. Sorry!