Greetings from the midwest from a long-time admirer of your university. As someone who follows college athletics in general and the Big Ten Conference in particular, I've found the comments on this site to be both entertaining and enlightening. I do, however, differ from two general themes: 1) UCLA is to be blamed for this situation, and 2) the Cal athletic programs are doomed to wander in the wilderness. While the future is challenging, it is not necessarily as dire as portrayed.
I can understand the anger and frustration regarding UCLA for their "secrecy" and "betrayal", but I believe that whenever an institution approaches the Big Ten about membership, all parties must immediately sign a non-disclosure agreement and The Cone of Silence descends upon the proceedings. If USC had approached UCB a year ago and suggested that the two schools contact the Big Ten, I would be surprised if UCB would have acted any differently than did UCLA. Perhaps UCB would have declared loyalty to the PAC and declined; if so I tip my hat to their quixotic gesture but question their wisdom.
The ultimate culprit was, of course, the PAC leadership for the past generation, but the situation was made much worse by the UC Regents. When confronted by the UCLA announcement, the Regents had three choices:
1. Follow their own written policy, take no action on the move, and quietly recommend that the UCB leadership contact the Big Ten to see if there was any avenue available for Cal to join.
2. Create a public circus, prohibit UCLA's move, and remove tens of millions of dollars from the UC system (plus in this case Stanford or Washington would have received an invite).
3. Create a public circus and accomplish nothing but humiliate UCB.
Well, we all know which course of action they chose. I would have thought the choice was obvious, but then perhaps this explains why I've never been invited to these august bodies.
A year ago the general public perception of Cal was that of the flagship of the most populous state in the union, and ranked among the finest academic universities in the world, whereas UCLA was but a branch campus that had a strong basketball program. Because of the Regent's actions and the tone of the media coverage, UCLA became acknowledged as the academic peer of (in some aspects superior to) Cal, and that UCLA was forced to assist its poor hapless "Little Brother". I do not understand why the Regents chose to denigrate their crown jewel in this manner. The Regents, not UCLA, should be the target of your fury.
The chances of a Big Ten invite, while not large, are not beyond possibility. First, you can forget about Oregon, the Big Ten will never invite the Ducks; the only three PAC schools that would be considered are Washington, Stanford, and Cal. I could imagine that Stanford might decline to join the brave new college athletic world of payment of athletes that may appear. In all but one respect Cal is an ideal Big Ten institution. You have high academic standards, are a leader in research activity, possess a large alumni base, are located in one of the largest media markets in the nation, and have extremely good Olympics programs (the Big Ten does care about these sports).
The issue, of course, is that your football and men's basketball programs do not have a significant following, even among your alumni. Still, as an overall package, from the Big Ten's viewpoint UCB is clearly superior to Rutgers and at least on par with Maryland. Alas, there is indeed a tide in the affairs of men; if UCB had applied to the conference in 2010 I suspect that you would have been admitted, but the additions of USC and UCLA raise the bar such that Cal is no longer financially additive on a per-team basis.
I believe that the most likely outcome is that the Big Ten will decline to expand for the next several years. If, however, the conference can attract a partner that would pay on the order of $100M for a 10:30 pm Eastern slot, and two of Washington, Stanford, and Cal would accept $50M/year for the life of the current contract, I can envision an invitation. The Cal/Stanford pair has the great attraction that non-football contests for the two could be scheduled with one trip for the current Big Ten schools. Another possibility is a Notre Dame decision to join the Big Ten, which would assuredly lead to one (and perhaps three) current PAC schools receiving an invite.
I wish you all the best, and don't despair; you just have to trust your leadership to be take vigorous proactive actions that will position UCB to be at the head of the line of the PAC schools if an opening occurs.