I need your suggestion, if filming and recording uncompressed to an external deck. How to record sound - can I record the sound to the same external deck in sync? Or do I have to sync in post? Do you have any (new) suggestions on a small and nice deck to capture the HD signal to?

Miranda makes a box that adds back audio and timecode into the SDI stream.
I don't have the exact number of the Miranda box but part of the model # is 800 I believe.

They were showing it at NAB '06 and I believe it has already been shipping.