I just rediscovered this thread after reading Trekweb.com's article. It's a fascinating read.
Take a look at this Phase II vignette to see the Phase II Enterprise launch from the Planet of the Titans spacedock:
[YT]http://www.youtube.com/watch?v=xim_PuEgRRc[/YT]
And now it has been!
I'm forced to wonder if Gene might not have used this as a sort of "work from this direction" sort of thing when they were developing the Galaxy-class for TNG cause there's several things on this proto-design that I can see probably getting incorporated later into the Galaxy-class.
I love this asteroid docking bay and hope it gets used someday in Star Trek.

[YT]http://www.youtube.com/watch?v=xim_PuEgRRc[/YT]