Player can get involved in numerous murders with little consequences so I propose adding few quests to spice things up.
Most obvious if you help Black Eels wipe out Scrappers some former partners of Eddie would approach you (also if you kill that guy with Cybernetic Eye for Foundry), maybe even wait in your room and explain to you that your little stunt has made big hit on their profits so they expect to be compensated for their "loses" by you, so player has to pay few hundred coins immediately and increasingly larger sum as time passes or do some other jobs for them which gets you even deeper into trouble (stealing from SGS armory and labs, smuggling drugs...).
Since these guys are real players they will know about every murder you ever committed (Blain, Grover, Treasa etc.) and your other activities (Abram tasks) so the more greedier bastard you are the more money they will ask from you.
High persuasion or intimidate should help you lower the amount you have to pay, delay payment or maybe even get you out of entire situation if its ridiculously high.
To get out of this situation you can either fight but unless you have really high level character you should have no chance, you can hire some low level thugs of the street but all they do is get killed and you have to pay even more money or pay large amount (10 000?), less if you did some quests, to Silas to help you out or maybe even Gorsky since he seems like a guy who could gather few guards willing to do some hard work for big payout (also militia commander in Foundry or maybe even Protectorate in exchange for you becoming their agent!?). Alternatively if you have made enough friends you can recruit them to help you for much less money (they still want money after you tell them the truth about what you got yourself into since they'll have to buy lots of bullets in order to help you
).
As last resort (if your character is so pathetic that you have no skills or money to get yourself out any other way) you can confess everything to Tanner who then orders Gorsky to set up full scale ambush and wipes out "the mobsters" to send them a message not to mess with you anymore but you get nothing for that (no experience, money, loot...) plus player should probably get punished with some pointless tasks and also needs to compensate SGS for their protection with large amount of weapons and armor or risk loosing your SGS status which puts you in danger once more (at lest until main plot puts you back on Tanners good side).
For more common killings like Blain you would get visitors to your room like Old Jonas and few of Blain's tough buddies which you can try fighting to death and get yourself killed or chose hand to hand combat (no armor or weapons) and probably get hell of a beating (unless your character is martial art expert) but surviving with some of your stuff taken as compensation after which you can let the whole matter slide or go for revenge and start whole thing all over again in never ending cycle or violence.
For most pointless killing like Grover you should probably get stab by some hobo next time you find yourself alone in back alley, nothing serious but enough to make you think twice before killing your next victim.
