The best way to do this in Marketo is via the rest API. Is this something that would work for you? This will allow you to clone a program every week and send the same email with dynamically populated contents. We have several customer that do this exact thing with great success. The reason this is best is due to the fact that you need to have either a newly created email or campaign in Marketo in order to get accurate reporting metrics. If you don't care about reporting, you could just setup a weekly recurring smart campaign that continuously sends the same email.
There are RSS to Marketo systems like Digesto available at a reasonable cost.
There was an Idea for this, but I think Marketo took it off because there are at least two options on Launchpoint.marketo.com.
Indeed, Digesto is a very good solution for this.