I attended a meeting of the Westminster branch of the OSC in January 2003 at Portcullis House, just next to the Houses of Parliament. David Bernstein was the guest, around six weeks before he quit as chairman, and he addressed an audience of maybe fifty or sixty Blues for the best part of three hours.
The forthcoming move to CoMS, as it was then known, was one of the major topics of the evening and he dwelled on it at length. He expressly stated that City's lease for the stadium gives the club an option to purchase the freehold at a price against which the rent paid up to that point will be set off.
He expressed the view that it was unlikely to be viable to exercise the option for 20 or 30 years after the club first occupied the stadium. Of course, ADUG's takeover rather changed that landscape. However, as has been stated by a number of sources, ADUG won't take the freehold as the purchase price in this event would be payable to Sport England.
Finally, and this is from an impeccable source whose reliability no one on here would question for even a second*, the idea of building a brand new stadium was developed in some detail, with the North Car Park selected as the site. The sticking point was that City wanted to demolish the current stadium when the new one was built.
That would have required Sport England's consent, and they wouldn't give it. Efforts were made to see if a sub-tenant could be found, perhaps Sale RU, the RFL, or even UK Athletics if we could remove the bottom tier of seats and squeeze a track back in. For whatever reasons, none of those were really viable, and in any case City weren't keen as having two large stadia on site would have inhibited other plans for the wider campus.
* - People can believe this or not, but it's true. For 3 or 4 years after the takeover, I used to receive information from two excellent sources about the development of the stadium and the environs. One had connections right at the top of the club and one was an external professional adviser. Both eventually moved on to further their careers and my information dried up.