Recently Dalauppror announced a new ruleset from Osprey Wargames based on the same mechanics of Lion Rampant, by Dan Mersey: "Rebels and Patriots", going to be released early 2019. The rules will adress the wars in North America from about American War of Indipendence to American Civil War at a large skirmish level, as Lion Rampant, Pikeman's Lament or TMWWBK. The temporal span covered by Rebels and Patriots is about 110 years. During this period some major changes in both technology and tactics occurred, but I believe Dan and Michel will be able to abstract a good Horse and Musket ruleset.
I'm not particularly keen on American Warfare, but considering the level of abraction of these rules, I'll definitively give them a try for Italian Wars of Indipendence (Risorgimento), since there was plenty of small clashes and few big battles.
I recently started collecting figures for that period, specifically Garibaldi's campaign of 1860 in Sicily, so expect more updates on this project in the next months! For the first time in my short wargamer's career, I aim to be able to play with a new ruleset at release day one!