Wasn't the "alternate ending" included on one of the US releases of MegaZone 23? I don't know how complete it was, but I know I have both US releases of it.

Where are you sourcing the audio? I remember there was a rumor back when the original ADV sets were coming out that they were considering including the audio of the movie on it, since they didnt't own the rights to the footage.

I've actually considered doing the same thing, so I look forward to your finished product. It's not a great movie, nor is it a great part of the series, but it's still part of the show's history and shouldn't be buried.