OK, I will do the v2.1 AVCHD :-) As to the MKV, what Mavimao said is absolutely right. And you can also make one from the AVCHD just as easily - most MKVs of films this length "obtainable"online are the size of the AVCHD or smaller. I wanted to do the MKV as a really high quality release before I get the BD out but to my surprise, the AVCHD is so good, it wasn't even necessary (I expected the AVCHD compression to be similar to the v1.0 but apparently the quality loss in v1.0 was caused by the editing process using lossy files and non-professional software rather than the final encoding).

As to h_h's 2.0 mix, I didn't include it because it simply doesn't really represent any of the theatrical or official mixes. I was even considering not using the 93 mix but in the end I did because that is a high quality stereo if you need one - 320Kbps encoded from LD PCM.

This leads me to a question about audio - how large will the lossless mixes be? I need to account for them when deciding on encoding bitrates of the other features on the BD.