Wow - I hadn't fully appreciated that you were planning multiple audio; menus & additional features!! When you said it would be 'ultimate' you really meant it, didn't you!!!
I completely understand your wish to be discrete regarding the detail of the project and your 'something' on disk two...better to work quietly away on that, I'd have thought.
As much as I and I suspect others here are dying to see these blu-ray quality releases in all their glory as soon as possible, quality takes time and dedication. I guess that you have to strike a balance between having a release and maximising the features that you want to include. It's easy for me to say don't compromise and in an ideal world that would be the overriding consideration, but as you rightly say, it could possibly take you forever. Perhaps a second disk subsequent to the release of the actual movies might strike the right balance....and possibly maintain your sanity?!!
In any event, there is no doubt in my mind that it will be worth waiting for - your 12gb releases set the standard for Star Wars in HD....this will certainly surpass them.