Just to be sure, are you aware you can supply an infinite amount* of subdomains to be signed? If you need a finite and determined set of subdomains, that's totally possible.

* Well, I'm sure there's a limit, I just heard it's more or less unlimited.

Edit: A bit further in the thread I read a limit of 100 per cert, except you can only register or renew a few per day. Never mind that being unlimited, then.