Hi
There is a very good and detailed orbat on
http://www.napoleon-series.org/ - go to the military section, campaigns and battles and look under 1812.
I have been looking at Borodino for some time and there is, in fact, very little information out there about individual unit strengths - in fact, there is considerable controversy as regards total army strengths. The best you can do, therefore is pick a set of numbers that you are comfortable with based on your research and then work out your own unit strengths based on how the totals divide up by the numbers of btns and squadrons present.
Not sure what scale of figures you are using but Borodino is an immense battle to try and tackle as a single project. You might want to think about focusing on individual sectors of the battle and to try to reproduce those.
By the way - I have no doubt that there are going to be a few borodino refights being planned as it is the next 'big one' up for a 200 yr anniversary after Wagram.
O