Recent WOJ has it that Little Chicago perished in the fire, neither Lea nor Mab saved it.
It was clearly Harry’s masterpiece as a magical artificer, and would have been of great use in BG, but it was not to be.
With Chicago rebuilding Harry has the opportunity to build Little Chicago II, Bigger Little Chicago.
As the Wizard of Chicago it is the obvious move to protect the City, and he could make Little Chicago quicker and easier than before, he has the practice, his hand is much better, and he has the time and money, and the help of the little folk in gathering samples. He has soulpower.
But Harry being Harry he is always thinking about making his stuff better, whether it is giving his staff an extra kick, or making the enchantments of duster last longer. You just have to look at the evolution of his shield bracelet.
There are a couple of obvious things Bigger Little Chicago will need, it will have to include Demonreach so Harry can monitor the locale and route to the Island. He may be able to use BLC to extend Demonreaches demonic reach across Chicago, allowing real-time communication and a massive security upgrade for the City if he can send someone down from within the City. Luring the Titan to the lakeshore shows the need for this, and Demonreach was shown to operate in a limited fashion with Mab’s aid in GS. It would allow for much better protection of St Mark’s and Maggie.
If Harry can use BLC to integrate multiple upgrades, what about one more? If Harry can plug his Amulet with his mothers crystal into BLC then he can use it to identify all way points in Chicago and to monitor them through Bob. Use it as a removable starter key to BLC.
With the NEXT BOOK (I hate the current title) we could see Harry do just this as a big New Years project