I made a site that checked for SSL cert expirations and misconfigurations, but I couldn't acquire any customers. I still think there's a business there somewhere, although maybe it really only sells as part of another product.

Edit: If anyone wants a script to check their certificates, here you go: https://gist.github.com/bretwalker/5420652. You'll just need to add in some sort of notification logic, especially for expirations, since they need to happen before a problem arises.