You mean a database of companies and blends - current place I an think of would be http://www.tobaccocellar.com/ - might contact them and ask if they'd share their current database?
Are you writing a plain-jane windows (VB)/db app or are you writing a cloud app, that could be accessible from phone, notebook and computer?
I would suggest the latter and then if you don't have a tobacco database let your users populate the content and make content updates globally over time.