Great use case to get the dashboard even if its not a perfect fit for the module.
I haven't tested this, but I think you could set your cadence for daily and then limit each email to the specific date you want it sent. The one catch might be how leads get pulled back in when they've exhausted the content.
Adam wrote an article on how to randomize the send dates at http://community.marketo.com/MarketoDiscussionDetail?id=90650000000PfgdAAC .The same principle can be used to set specific dates.
Another idea is to set the engagement stream cadance to daily and set the availability of the campaigns/emails on only 1 single date and move them to the top of the stream (highest importance). This way on those specific dates your selected mailings will go out.