As Natnic mentioned Rogue has the option, but I believe the switch is toggle switch on the back of the unit. So to access it you must reach around the back of the pre to flip the switch. A 66 Magnum just sold the other day for $699.
Another option, staying in the Anthem family, is the Pre 2L. It will mate well with you MCA 2. I saw one go recently for around $600. Do a search here on the 'gon for more info on each. Good luck.