When I did a brief stint as a pirate, I charged 1mil - 2mil max.
The rationale behind this, was that a.) I wanted to get paid with a minimum of tantrum throwing and b.) encourage the trader to rp without causing him too much inconvenience. I would rather rp and tax then chase someone across a system only to blow him up.
I've traded since forever and let me tell you, I've never been too happy to bump into a pirate asking for more than 2mil after a long, tedious and inconvenient run. Thus far, I've always been able to cut a deal with pirates - fortunately.
If you want boatloads of cash, trade like everyone else. Taxing is primarily for rp-purposes, not to get rich. It's also not to a punishment for traders, who don't use trade lanes. Kind of an odd argument. To my knowledge, trade lane users get pirated too.
