Howdy.
I decided to try a mod in order to make the game look a little more pretty, and it worked.
The links are:
http://www.mbrepository.com/file.php?id=625
and the quick-fix (you must download this):
http://www.mbrepository.com/file.php?id=891
I have a GMA X3100 video card on my MacBook, and this actually made M&B run better. The draw distance and massive amount of people on the field bogged my computer down so I could only play it on low, and it would still drop to below 30 FPS, which was disappointing. After downloading this, I'm running everything on high and it looks great AND is running a higher framerate.
Since the installer can't find the Mount and Blade folder, you have to browse for it by going to your Hard Disk Image > Users > You > Library > Application Support > Crossover Games > Bottles > Default (Or whatever M&B is installed under) > drive_c > Program Files > Steam > steamapps > common
... and you're there. I'm pretty sure you can only play M&B from Steam in Crossover, so I didn't bother posting the route if it were downloaded from Talesworld.
Anyway, hope this works! Be sure to download the quick fix because it didn't work for me without it.
Note: I haven't tested any other mods but if I do I will be sure to say if they work or not.