This is a topic for anyone who is not interested in the Humanity Loss rule. Such a rule feels like it was shoehorned in to maintain game-balance so players would no layer chrome on the characters, but the cyberpunk genre is about enhancing characters with cybernetic upgrades, and they should be able to modify themselves with any number of cosmetic enhancements as easy as one gets piercings and tattoos today.* After all, should anyone with piercings, tattoos, cosmetic surgery, prosthetic limbs and medical implants loose their humanity over them? Hell no!
The only way I can rationalize Humanity Loss is that some powerful enhancements can make someone feel like they are all-powerful and go on an ego-trip. But that is hardly a reason to to go outright insane, and an ego-trip falls apart when someone else puts them in their place. I seen an anime were drugs are used to provide a means to better interface with cybernetics, but there were big holes with that method too.
My alternative is to burden players with upkeep costs. Much like the normal cost of living, any character with cybernetic enhancements needs to put time and money in to keeping his systems charged and running, with regular check-ups. One of the Chrome Books make note about stuff braking down, but I would rather have a simple, abstract system for that. Such a rule (that I have yet to develop) would require the players into allocating money into different forms of upkeep. You would put money into Lifestyle (food, shelter, utilities, style, etc.) so the PC can be happy and healthy. You would put money into Resources (allies, contacts, property, investments, etc.) so you would not loose them. And you would put money into Cybernetics and into Equipment to keep everything in working order. You can let the costs slide or put less money into them, but that would risk something bad happening down the line (typically as a random mishap). You can put more money into them to lower risk of mishaps.
OK, that is my idea. Do anyone have their own ideas on allowing more cyberware with limitations?
*Seriously, the game treats the Mr. Studd™ implant like the tramp stamp of cyberware! That implant should be so common, it should default, and if you want anything bigger, you'll end up with something that could satisfy a frustrated mare!