Itchy,
Triumph And Tragedy is a set that may well be ideal for your needs. Although marketed as a set of rules for the early 20thC, it works perfectly for late 19thC. Indeed, it was apparently intended for Darkest Africa games when first devised. It also enables you to use "heroic" [or not so heroic] characters, which adds even more fun.
http://www.triumph-tragedy.de/It is available from Pardulon in Germany. The shipping is very reasonable and you'll get it in a matter of days [much quicker than TSATF from the USA]:
http://pardulon.com/catalog/index.php?cPath=53&osCsid=b766b55d0279bb0b49381aae9872e0c3The third good thing is it was written by two fellow LAFers, Bjoern and Chris, sold by another, Jens and rules updates etc are notified in the LAF's own T&T board.
How can you not want it!

Seriously, it is well worth getting T&T, as it is more of a "skirmish" game whereas TSATF is better for larger Company or Battalion sized games.
There is also GASLIGHT, which whilst being a intended as a "VSF" game, also works perfectly well for historical games. Like T&T, it also enables you to add a variety of characters.