My sales team is at a conference in Europe (I'm in US) and we're hosting an event that we've been promoting for weeks now. I'd like to be able to schedule an email to send to them that will populate the most updated list of RSVPs that came in through our marketo event registration form. Is this really something I have to do manually 6 hrs ahead? Or is there a way of sending some sort of smart campaign?
Until smart list subscriptions come out this year, no.
You will have to send a manual list in excel.
One option does exist - if you have RCE, you can use the Lead Analysis report to pull in a list of Leads which are in the Program of a certain status and put in the columns the fields you want.
I'm pretty sure you can get the Program info you want in LA reports, even if it is only membership. I don't have access right now, but it's possible the PM report also works, but I'm pretty sure it won't give you a list of email addresses and names.
If your sales guys use Salesforce on their mobiles and tablets (or laptops), how about a workaround? Sync the registered leads to a Salesforce campaign. Create a lead/contact view using the campaign name and Registered status. That way they can see registrations in real time and don't have to wait for your email.