As I have been planning for when my Epic-X arrive (Which I am EAGERLY anticipating BTW) I have found myself running the numbers for the storage, and run times for the RedMags over and over. So instead of doing the same thing over again, I put together these charts for reference and I thought that others might benefit from them as well. From what I have read so far, with the Epic-M's the run times for the 128GB RedMag have been close to what has been published, so extrapolating those numbers out, I arrived at these numbers.
Caveat Emptor: All things with Red are subject to change. These charts are meant for general help in planning for the Epic.
Oh, and here is a PDF of the same: