I had an idea and you have probably already read many of the same but here goes nothing...
What about a very expensive upgrade to your PI for a drug lab.
Once you have purchased the lab you can make some or other entry lvl drug (like cannabis or whatever) until you reach a certain skill level (almost like what one does in the Crimes section). Once you have reached said skill lvl another costly upgrade becomes available to your drug lab which then opens up the next lvl and so forth until you can produce Xanax?
Perhaps you can employ staff to work for you and pay them minimum wage (as most drug lords do) to work in the factory
Other citizens can try and mug you at the lab to steal your product if you just leave it lying around in the lab or something like that...