Napoleonic skirmish rules for about 12 figures per side?

[levied troop]

2 HourWargames rules system is interesting, thoroughly enjoyed their 20thC set and there is a Nappy version:

http://www.twohourwargames.com/95th.html

If budget is an issue, there's a free version of their 20th C set on the site, so you can check out the rules mechanisms for free before committing.