Hi Grant,
Good advice--unfortunate if there isn't a method for this in Marketo or SFDC. I was using the term lead loosely. Hot leads where someone filled out a form or requested a trial would go to the top anyway based on score, and I have that set up now. The issue is more in making sure that cold leads (i.e. where someone jhas only opened an email, etc) are followed up on in a timely manner. By sending an email out each day that only populates the ADRs queue with enough leads to last that day, then the gap between email send out and phone follow up is minimal. By putting a lot of cold leads into their queue at once, then it may take days for them to follow-up and the lead becomes even colder.