On the left is a stock Wargames Foundry 'Boer with Pistol' painted up in colors that, one hopes, are more suitable to an American Banker of the Wild West. On the right is the same figure, converted into a Mexican Federale officer from around 1913.
The brim of the bowler was cut off from the back and sides, but left on the front where it was filed into correct shape for the peak of the cap. Then a bit of putty was pressed onto the top of the bowler, and sanded to the correct shape for the cap.
Not many Federale officers would have worn beards in 1913, but filing it off was just too much work. Looking back, I'm not certain why I didn't just change heads.

Oh, and here's an Apache in a Federale shako.

More images over here at the gaming club's web site.
http://thebengalclubla.com/tbc_gallery.asp