Hi Paul,
First of all I want to welcome you to the forum
. Ask and there will be many answers from all corners of the world
As a start you may visit the Nafziger Collection
http://www.cgsc.edu/carl/nafziger.htm
Much depends on the time and the geographical area you are interested.
If Leipzig is yours you will have Corps in size of Divisions and Battalions with less then 300 men. If its that what you are looking for...there you are.
I once tried myself on the german campaign of 1813 and focused on Ney's III.Corps, which was one of the largest of this Army 30-40.000 men and over 100 guns. Btw., I did this in 15mm but my interest dried out after the 3 of 5 Divisions. Now the minis have found their final resting place. But that is another story
Hope that helps
Happy New Year
Günter