Hey, not sure if this is already widely known, but my friend told me today he found out you can activate the old M&B by using your Warband CD key. I tried it out and it works! So for those who have been thinking about purchasing M&B, you can just download the enchanced version
http://www.moddb.com/games/mount-blade/downloads/mountblade-1011-fall-2009-enhanced-version and apply there your Warband's key. Hopefully, we saved somebody's 10 dollars.
P.S. would be nice if you upvoted so more people don't waste 10 bucks :(