Sending newsletters with Rails

Hi,

I'm using ARMailer to send emails, but I still need to iterate over recepients and call deliver_email method for each recepient. It works fine in production with small number of recepients, but if I had 10000 of them, wouldn't rendering 10000 (unfortunately HTML) emails and saving them to db take a while?

Is there some way to cache generated email view and just substitute "To" field in email header? I'm using Rails 1.2.6.