I've pondered this extensively.
Why is Hendak the new owner of the Copper Coronet by default?
Wouldn't he just be happy with being set free, and then be on his merry way?
I would much prefer having the PC assume control of the CC, and being able to influence it via alignment.
Goodly(I think this covers neutral, too);
Good natured "boxing" type matches, non-lethal entertainment. Think Ultimate Fighting Championships. There'd be a certain establishing cost to redo the interior of the CC, the current "pits" are just crappy looking - and facilitate a better spectacle.
I'm thinking an Arena type environment with a large central pit, and a viewing area all round. You could then have quests do go around various places and recruit known boxers/fighters for celebrity type matches, and a bigger crowd. The pit would give a weekly return, continually increasing with the number of celebrity fights you've had. (Those fights really bring in the crowds, y'know.)
Again, these fights are non-lethal - based on the "I Yield" type scenario. (Just like we've seen in Ust Natha..)
Maybe these recruited fighters would become "regulars", and thus earn part of the overall revenue, and either the backroom.. ahm.. 'love' rooms, and the cells would be turned in to private quarters to facilitate this.
It could be run kind of like with the playhouse, you have to find a competent manager, someone to announce the fights and get the crowd roaring (and betting) - and other management things like that. Once you've set up the initial things, it'll pretty much run itself and you'll get weekly revenue like with the other strongholds.
Evil;
It's obvious, to me at least, that the slavers would have a part to play in this. Basically you'd investigate the slaver compound, force your way in - pummel their leader and take command. This would be slightly more expansive than the good route, in that you don't necessarily need to destroy the slaver compound to gain control. You'd take over the Athkatla slavetrade, importing slaves to fight in the pits, Bernard would probably disagree vehemently, so there'd be a need for a suitable replacement. (Either making Bernard do a walk-out, or simply killing him - perhaps by some gruesome spectacle in the pits. Him vs. Rabid Wolves for example, getting torn a apart limb from limb.)
People would be able to bet, and would have to pay an admission fee. This would cater to high-value clientèle and be closed to the general public. Only the wealthy and powerful need apply.
Obviously this would generate a lot of wealth, both from the selling of slaves - and the freebie fighters you get by using slaves and pitting them against each other, or against various animals or other similar beasts.
Quests could be that some wealthy nobles ask you to "remove" someone they have issue with, and watch them die in the pits. Basically something like the Mind-Flayer control circlets could be used - slaver circlets, used on people - cut scene - they are in the cell area.
Obviously you'd want to profit on prostitution as well. I guess neutral characters could swing either way on the prostitution issue.
Also might be interesting to toss Anomen in the pit, and see how long he lasts
Obviously there needs to be a drawback to this, which I think might be of the "legal" nature, in that there would be undesirable attention from righteous knights and the like. Perhaps bribery of government officials, or even elimination of some would be desirable.
I feel this would fit in nicely with something like "Assasinations", to give more variety for Evil players.
That's just a rough outline, but I've certainly spent long enough typing it out if it's entirely useless as a concept.
Give me some thoughts!
Edit;
Oh yeah, both cases could certainly utilize "Fight the Bhaalspawn and win x amount of money." - whether it be to the death or not, would be a PC choice. (I.E dialogue before death and having the option of killing, or displaying mercy..)