Yeah but I have done that by lowering my tax contribution too. In fact if I move into one of the new mega-super-skyscrapers that this will surely result in I may end up paying so little in taxes (because so many people will share the ground) that it won't be enough to pay for the police and fireservices, which surely will go up because it is more expensive and difficult to fight fires in so tall buildings.

So in effect I have shifted most of my tax-burden off to others, land will have very little value (because it will have to be taxed more and more heavily).

Of course you can mix it with older taxes, but then you have the problems you had with them too.

It's relative to the value of the land though. The value of the small area your skyscraper occupies in downtown Manhattan or wherever is probably extremely valuable. Thus, high land taxes to be split among the occupants. It's hard to say whether your tax burden would go up or down without hard numbers, though.

Keep in mind that the land value would be the factor determining your proportion of the the overall tax income. If tax receipts go down, then the amount of tax charged per unit of land value would go up. At some point you will be unable to use less land without incurring far higher costs - e.g. tacking on ten floors on that skyscraper will require complex enough construction methods to not be cost effective. That's before considering any kind of planning consent.