Hi Matthew,
have you tried to use BFD to speed up OSPF convergence, i.e., time to detect a failed neighbor (Metro-E indicates that you have a Layer 2 service and currently use OSPF directly between your DC devices)? If you have several E-Lines instead of one E-LAN you could consider point-to-point link-type configuration to possibly speed up OSPF convergence.
Perhaps you could benefit from using OSPF areas, if you are concerned with two many routes affected by a failure in the other DC, or just to keep events localized in one DC if possible.
I am not yet convinced that the added complexity of using two routing protocols with redistribution is needed, but then I do not know much about your situation and what you have tried already.
Why do you think that using iBGP would speed up convergence? You seem to have an idea what it shall accomplish.
Thanks,
Erik