In one of my forthcoming books, Unchecked and Unbalanced, I discuss a number of mechanisms for limiting the power of government. You can think of these as mechanisms for achieving virtual secession, although I do not use that term.
The problem with physical secession is that it is very difficult to achieve critical mass. There is probably not much overlap between the people you want to live with and the people who want to choose your particular form of government. The vast majority of us put up with government we dislike in order to live in proximity to people with whom we want to work and play.
With virtual secession, you could still live in San Francisco or Manhattan or Silver Spring while seceding from much of the government at the city, state, and Federal level. You and your next-door neighbor might belong to very different governmental units.
Suppose, for example, that instead of having your taxes allocated for you by legislators, you were given a list of programs and could choose how to allocate your taxes. What percent of your taxes should go to TARP? What percent should go to fund the mohair subsidy? What percent should fund DC school vouchers? What percent should go to Barney Frank's affordable housing initiatives?