I've spent the last week checking out different mods for M & B.
Some good stuff, some buggy, some just didn't tickle my fun button.
Mods can be found here
http://www.mbrepository.com/modules/PDdownloads/Once you really have a handle on Mount and Blade, have captured castles, mastered combat, etc.
Here is my recomended list for bringing M & B back to new life.
Band of Warriors mod
Instead of 4 heros, you can choose from up to 24, vastly increased tools for changing their gear, assigning atribute, skill and weapons points.
Manageing how they go into batle, which weapons they choose etc.
Plus this mod brings the Dark Knights back to M&B. Don't camp out in the field at night or they will pay you a visit!
Some new weapons, some changes, ran solid for both Bison & myself.
Eagle and the Radiant cross mod.
Much harder over all than Vanilla M & B. Many new weapons, reworked units. Including Flintlock Pistols and gun toting bandits.
Just surviving and keeping the money coming in is a lot tougher. Castle sieges are VERY hard now.
Lots of new troop types to figure out the upgrade paths for. And many of the higher foot troops now have good armor and long pikes.
Makes life a lot tougher for your hero with a horse and a lance.

I can see that I'll be playing this mod for months to come.
Good warhorses now pay a big maneuver penalty for all that armor. Instead of 35-40 speed and 35 + maneuver, your likely to see 40 speed and 18-22 maneuver.
In short that warhorse drives like a mac truck, give me 40 acres to turn this rig around!
EGII Bandit King.
What can I say, if I could pull the best parts of Radiant cross into this mod I'd be happy for life.
You have many many more options as a free man. Mercanary contracts with other factions.
Or capture a castle and start your own faction. I captured Sumgetche and picked up 5 fief towns along with it.
My only problem now is trying to take a Swadian Town. Many great new units, lots to do and explore.
It does have a missing mesh for a brown horse, which is annoying. Hopeing for a fix soon.
Calradia at war was buggy, not much in the way of changes, I didn't really care for it.
If you've been playing with a mod other than these let me know how you like it.