Going back to the slave license thing. It does sound interesting when mixed with the idea that zodiac44 had earlier about some people willingly becoming slaves. Gonna sound odd and probably rather code intensive, but how about 4-5 types of girls. Free girls/Market or Regular slave girls (Legal+Registered)/Contracted Slaves (People who offer themselves for shelter/food/debt and is legal)/Monster girls/Illegal Slaves (girls you kidnap and forcibly brand). The license could be a 'registration fee' *coughbribecough* to convert your Illegal Slaves to regular slaves so if you are raided you are not fined for them and can sell them. (you cant tell me such a corrupt gov would not keep track of slaves for possible income *coughblackmailcough* purposes). Also maybe have to purchase licenses for certain acts/jobs. (ex. Tentacle monster keeping license, License to keep monster girls legally - seein as they are liable to tear someone apart if they go berserk, Movie Production license, Alcohol license, Gambling License, Stripping license, various others too.) You COULD choose to do the acts w/o the licenses, but if caught you could be fined and lose rep. Also would have the added bonus of making the 'bribery' option at city hall more useful since gives even more reason for gov not to go snooping around your businesses. By having the licenses it would improve your rep or something.
Perhaps the 'take a walk' action in town could have a few different options added to it as to where you take that walk. Say you walk through the slums and find a starving girl on the streets with no money/home and she offers herself as a slave (which would be legally free as a 'contract'). Also a wealthier part of town with bored rich daughters wanting to rebel against their parents or something willing to work as free girls. Maybe 3-4 areas of town you can choose to 'walk' and search, with certain areas having better chances of finding girls but lower quality or something.