One of my absolute favourite historical/war epics is Sergei Bondarchuk's Waterloo (1970).

The movie has mind-boggling battle sequences utilising thousands of Soviet soldiers as extras, along with an entire cavalry brigade. Along with the equally epic battles in Bondarchuk's War and Peace adaptation, it's probably the closest we'll ever get to the sheer scale of Napoleonic battles. Especially considering it's all non-CGI (even Ridley Scott's upcoming Napoleon will use a lot of VFX, judging from behind the scenes shots).

However, the movie was a flop and one of the last of it's kind. Perhaps this is because the drama (and more intimate side of things) is not so good, and definitely inferior to War and Peace. Chris Plummer is outstanding as Wellington and really gives off a "pompous aristocrat" vibe. However, Rod Steiger is IMO completely awful as Napoleon and delivers some of the absolute worst lines of the movie (he also hams it up many times). Other than that, you have a relatively weak supporting cast and Orson Welles in a two-scene cameo as Louis XVIII.

Ironically, the movie's box-office failure was one of the reasons Stanley Kubrick cancelled his long-planned Napoleon project. However, the movie has since become a cult classic amongst Napoleonic era geeks and fans of historical epics in general.

For interest, it's complately available for free on YouTube, including a fan cut with stills of deleted/lost scenes (the movie was made back in the 70's when saving outtakes was almost unheard of - especially given it flopped - so the deleted footage is probably lost forever).

Interestingly, Kubrick's Napoleon project has been mooted as a HBO miniseries, with reportely Spielberg producing and the now disgraced Fukunaga directing (Spielberg himself also seems to have been named director at one point). It remains to be seen if it actually ends up being made, especially after Scott's biopic is released. Most likely though, the battles will be CGI-heavy instead of the real extras (from the Romanian army) that Kubrick envisioned.