I'll be away for two weeks with my HD2000 in Turkey so there will be no new posts and I will not be able to respond to comments until I am back. The lowlight capability of the HD2000 will be tested since there will be many visits to mosques, churches, museums and other indoor sites where flash and tripod are not allowed.
Meanwhile I did a test on the 4GB file limit and the gap between files. This 4GB limit arose because the SDHC cards are formatted in FAT32 and 4GB is the largest file that the system can handle. (This is also true of all other camcorders that uses the same file system.) Once the video reaches 4GB during recording, it will stop and the file is saved and recording then continues with a new file. This is all done automatically and will continue until the recording is stopped manually or the card capacity limit is reached.
This is what I found out for the HD2000. There is a 30 seconds countdown counter in red on the LCD screen before the 4GB limit is reached. The gap between files (end of the first file to the beginning of the second file) is about 10 seconds in my measurement. These files are marked with a special icon in the playback selection screen and during playback they are continuous, i.e. it moves from one file to the next without stopping, like one continuous file. In fact using the fast forward and reverse will move across files as if they are one continuous file but each file has a separate name.
Hope this is of help to those interested in these details.