My source deep inside the workings of General Dynamics (stay safe buddy...they're paranoid) is telling me that they're going with a derivative of their LAV II Technology Demonstrator.
Interesting but it may all be academic.
The MPC
The Marine Corps hasn't.
Why?
Because the Marine Corps historically chops boat spaces first and equipment last.
You haven't heard a Marine General Officer speak on sequestration because the first move will be to reduce the ranks. (Read a Marine Corps Times article on it here...no info on the Marines is given) If it hits as hard as some indicate I would expect at least 10,000 Marines released from their contracts for the good of the service before the end of the fiscal year.
Once they get around to equipment what do you think will be first? The F-35 is protected. The MV-22 is the Marine Corps pet. The JLTV is a joint project with the Army and we're committed to buying the first 5000. That leaves Marine Corps specific programs. The MPC. The ACV. The CH-53K.
If it hits and if it sticks the Marine Corps might not seen any of those projects reach the fleet.