I almost misread this and started listing all the various *infantry* casualty figures out there. But, yes, *cavalry* casualty figures are harder to come by.
You might try these two packs from the Perry range for French cavalry casualties:
FN29 - "Light horse lancers of the line hit by canister / volley"
FN70 - "Cuirassiers hit by canister / volley"
Sascha Herm did a lovely job of painting the lancers a while ago:
http://www.sascha-herm.com/Lancers01.htm
And there's Foundry French pack FN324 "Casualties" that is a mixture of infantry and cavalry figures.