I really don't like the mixed province look, so I stick with a single province. I paint mine in one general scheme, with some slight variation in each unit. At least one of my main colors is on pretty much every unit though. Some of my characters don't follow this, and that is mainly my wizards.
I quarter the uniforms on my statetroops. So halberdiers have right shoulder and left leg burgandy and the other quarters get yellow, spearmen have them reversed. Knights and Pistoliers are slightly different. The pistoliers have alternating puffs painted burgandy and yellow on their arms. My swordsmen, who are the old Regiment of Renown models Vespero's Vendetta, have white shirts, black high boots, and burgandy cloaks with yellow trim. Each troop unit is different, yet on the table the overall visual impact is that they are one complete army.
This allows me to use the same color palatte for the entire army, yet not get bored with painting those colors repetitively. Overall I use three main colors. Burgandy, Yellow, and Brown. I also use three other colors to a lesser extent: White, Black, and Light Blue. Those 6 color make up about 90% of my army. The other 10% is mainly my wizards who will eventually run the gammut of the color wheel, Knights, and a few other characters.