Another valuation/taxation scheme I've read about is: you can value your patent however you want, and it's taxed based on that value.
The kicker is: the values are public, and if anybody wants to buy it for something higher than the assigned value (or maybe some fixed percentage above the assigned value), you HAVE to sell. Of course, the buyer is then taxed at the higher value.
That seems like a terrible idea! If you underestimate the value of your invention, some big company can own it for $n+$.01. Or if you have invented something valuable but it takes years to get to market with it, you can go bankrupt in the mean time, or have your ownership eaten away by investors who suddenly have a ton of extra leverage over you.
The kicker is: the values are public, and if anybody wants to buy it for something higher than the assigned value (or maybe some fixed percentage above the assigned value), you HAVE to sell. Of course, the buyer is then taxed at the higher value.