OK, here is another quick thought.
OPEN ONLY OPTION
How about the option to flag your character as "Open Only"? Once you make this choice only the Open option is available to you.
While the appeal of this might be limited it could provide some interesting opportunities that aren't workable with the current modes.
These are the most obvious that spring to mind:
1) Bounty system
Player kills by Open Only players would result in a murder tag and a separate (very large) bounty that cannot be removed except by being claimed by another Open Only player. This would add a little more consequence to murdering another player and also make player bounty hunting more viable, as they would not be able to remove it or hide in solo. The tag and bounty would apply if you kill anybody who is not already tagged as a murderer.
2) Most Wanted List
Basically a list of the biggest murderers in game, ordered by current murder bounty. Caters both to those who crave infamy and those seeking to bring them to justice.
Interesting idea, my initial reaction is I like it.
Going to give it some thought, as at 1am my brain is not on full power
An interesting idea - but how is that going to work when I am sent to Uttanoplace, where 56k dialup is still a luxury? Should I have to clear my save in order to play the game? That connection won't support Open, and we only have one commander slot.
If I've understood, this is in addition to the current set up, so unless you sign up for being locked in to open - you'd carry as normal like you do now.