That sounds like an interesting proposal but I don't know why we'd want to encourage people to sell their investments in companies. Long term investments in businesses help the economy grow. Fencing off land and not allowing other citizens access to it has several negative externalities (eg. what we're going through in California now).
From a tax policy standpoint it would be the same thing -- you're taxing wealth instead of capital gains. We don't do that for any other asset class.
But, if you're "investing" in a public company by buying stock, unless its at the IPO, the money isn't going to the company, it's going to someone else who owns the stock, the same could be said if you force people to sell private investments to other people.
No, I'm not proposing we tax wealth instead of income and capital gains.
I think it would actually be positive for other places in the country if companies decide to open offices outside of California to locations where everything is cheaper.
http://www.landvaluetax.org/current-affairs-comment/winston-... says it better than I can