This would make it so much simpler to get Marketo's data to do some real analysis. Presently, pulling this data requires either developer resources or a fairly expensive subscription to an integration service (Jitterbit, Progress DataDirect, etc.). Wish this would see the light of day, or at least have its day in court.
We have bumped into the same issue as you had before while we are trying to extract Marketo data to SQL server database to build some analytic reports, but it turned out to be hared to achieve with Marketo standard API.
Finally, we developed our solution, and you can see my reply in the middle of this post: Replicate Marketo Database
We actually found an out-of-the-box solution for using OData with Marketo - Progress DataDirect. They have a Marketo connection that you can consume with OData (or ODBC, which is faster). It uses the SOAP API rather than the REST API, so it is a little bit slower, but it does what it needs to in a stable and consistent manner - we've been using it for over a year now.