Thinking from the perspective of an habitual offender...
"Gee, I can rape as long as I sell my stuff! Let me go rob some people to get some stuff to sell!"
Or from a wealthy offender...
"Gee, I have lots of cash! Let me kill some people!"
Exactly. This is one of my many problems with a completely free market justice system. People NEED to be punished for wrongdoing.
Though I know neither of you care, this doesn't help Rothbard at all since he argues that deterrent is not a valid justification (by itself) for a punishment system.
Now, rape is no small crime. The amount of restitution demanded would be very great. He'd have to steal a whole lot of stuff to have enough to pay off a rape. If he didn't get killed while robbing dozens (or more?) of people of all their possessions (which is unlikely), and then committed the rape, he'd still be fucked. He couldn't pay off the rape with the stolen wealth, since he'd have to pay all of that back and more (for inconvenience, threat to safety, psychological trauma, etc.) to those robbed. Robbing to fund rape would just get him into far more debt. Sure, some people will not understand this and will act irrationally. But people will act irrationally under any system of punishment.
For those that are ridiculously rich and can somehow afford to pay off murders and rapes, they still suffer a terrible reputation loss. Someone who spends his amassed wealth on a crime hobby would be quickly recognized for what he was and ostracized. Anyone who saw him would be on their guard and ready to shoot him. He wouldn't have the services of a protection agency. He wouldn't have the services of any insurance companies. He wouldn't even be able to go to the grocery store. He'd have to live on his own property as a hermit, with no business dealings with anyone.
I wasn't even considering deterrence- some people are gonna do what they will no matter what.
There are too many holes in your theory- this whole discussion is full of loopholes on both ends, realistically.
On your end, on rape, what if he decides he simply won't pay up? Or he is offered a ton of cash to commit the rape in the first place by someone with a sick fetish? Cash won't cut it, for me, neither does jail time. But I don't expect to ever see a society that offers anything other than jail.
As for the "rich" side- I don't think anyone would ever fully be ostracized. No matter how twisted, someone else can relate to that human condition. Plus, greed will take care of that in many instances.