Looks like there is indeed a cap. Not sure when it was added.
Here is the first game I found with more then 10k deployed. Interestingly the Players tab says that he receives 10k, however the deploy was higher (see red last two turns).
EDIT: Dah, forgot the link.https://www.warlight.net/MultiPlayer?GameID=4221202
Edited 9/10/2017 15:16:53