I think that a much earlier PoD than 1806 is going to be needed to pull off Bavaria becoming the dominant German power and unifying the area, unless Napoleon suddenly gets a massive hard-on for Bavaria and gives them more land than OTL, and even in that case, the Kingdom of Westphalia would still be more likely to unify Germany, although in this scenario it doesn't matter who unifies it, as it will definitely be a French puppet.