Hello
We have a few customers that send out newsletters every now and then.
Right now we have a whooping 6k emails in the mailque. is there any way to limit how many mails a user can submit during a giving period? (ie x mails/hour)
OMG that would be cool indeed. Would also limit the amount of outgoing spam 
Been waiting on this for a while. Hopefully soon.
As much as you try to protect the server, if a user has a easy password it can (will) eventually be hacked and used to spam. This outbound throttle would be great to save time of trying to get an IP unblocked.
Well the latest version of cPanel 11.32.2 not only has “Maximum Hourly Email by Domain Replayed” setting but also has “Maximum percentage of failed or deferred messages a domain may send per hour” Now that is nice real nice, because if you have a legitimate user sending illegitimate emails out but they have a excessively high failure rate that will get your IP banned quicker than a lot of mail per hour.
So hope fully when this gets attention both will be looked at once.