I have a quick beta of the MediaTek GPS parser for Ardupilot 2.6. Quick caveat - I don't actually have this module in my hands yet! I just modified Jose Julio's parser to match what 2.6 needs and read the data sheet on the new protocol. So, if someone who has the new modules could try this out and let me know if you are getting the right values, I'd appreciate it!
Set your GCS_PROTOCOL to 4 in your header file.