Customizing Chat bubbles by SIM would be handy, and possibly save users some money.

I am an expat and on more than one occasion have recieved messages from my home country and replied without checking source and sending SIM. Then getting the dreaded message that I have activated international roaming. Being able to differentiate by colors would be great and would not take up any screen space. I for one would do shades of green for my current location sim, and reds for those that might cost me money.