Let's see if I can get this right:

With the Gnome editor, elite units will have SAMURAI(YES) in column 26.
Fast units (infantry) will have speeds 6, 12, 13 (march, run, charge), as opposed to 6, 10, 11 for normal speed. Slow infantry are 4, 8, 9. Fast cavalry are 9, 24, 26, regular are 9, 20, 22, and slow are 9, 12, 16.
Impetuous and Disciplined are column 57. DISCIPLINED is disciplined, UNCONTROLLED is impetuous.

For the vanilla game, the file to look for is crusaders_unit_prod11.txt, should be at the top level of your MTW install directory. There's a lot of stuff in there.