Yes, 3.0 will come in 1080p. It would be interesting to know, in which GB regions the 1080p version will be released, BD-50 maybe? If it would be a BD-25 release, I would personally prefer 720p in this case because there is enough space for a higher video bit rate which is making a 1080p version obsolete, like the current releases. I did not notice any great difference (besides the colors!) on my calibrated TV comparing a screenshot from the official Blu Ray with a identical frame taken from the DE.
In that case, I would prefer a BD-50 1080p most definitely.
vfx: Here’s what I did with Harmy’s - include my 8 audio tracks and link to them in Encore as normal. I just reused AC3 tracks that load properly. Export the whole thing, open the image in AVCHD and replace the audio tracks and re-save it.