Do they make a SS Charger?
• There was a stainless charger made for, I believe Ellet Bros. a year or two ago. It had a brown laminate stock rather than the black laminate.
How hard would it be to make a Charger silver?
• No more difficult than making a 10/22 silver.

Strip the finish off the receiver - they're all the same underneath. The trigger housing though, being polymer would need to be changed out with a silver one if that's the look desired.
What does it take to legally make a Carbine into a Charger?
• 10/22 receiver to pistol = Class III so a bit of paperwork and $200 for the tax stamp. Once done, that pistol receiver is just that, it's not a carbine any longer. Keep barrel length and OAL length to it's Class I minimum and you'd be all set w/o the tax stamp.