A talented wrought iron contractor can add the extra 12" to the top of the railing and can detail the new wrought iron to make it look like it was originally designed that way.

You should look for local shops who are willing to do some design drawings to show you what they have in mind.....

Additional Photos

Agree with Lampert Dias. Another option is building a raised curb and installing the rail on top.

remove top handrail and add more iron to it to raise it up ,replace handrail and you get this look.
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Thanks for the feedback everyone. I'm failing to find any contractors in the Chicago area that can handle this type of work. Would anyone have any suggestions for who I can reach out to?

Just did a google search for "ornamental iron chicago" and found many places. Take a look :)