Osprey/Slitherine will be releasing a set of Napoleonic rules to compliment their Ancients and Renaissance sets. These will be released in March of next year (in time for me Birthday). I could not get much from the website but it will use Battle Groups and mentions correct formations so I assume it will really be more directed at 15mm and larger, possibly 10mm but not block based 6mm. It will be interesting to see what comes from these rules and how they differ from The Ancients, but then again I have yet to get the Renaissance rules for my ECW army and don't feel any rush, first I need to get the Ancients down.
The rules are listed at £25 and can be pre-ordered via the Osprey Website.